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DICTIONARY 



OP 



CHEMISTRY 



AND 



MINERALOGY, 



WITH THEIR APPLICATIONS. 



By ANDREW URE, M.D. F.R.S. 

PtOFISSOK OF CHIMI9TRT IH THK ANDERfiOMXAN UMXVSRSITY, MBMHBR OW THK GEOLOGICAL 

AKD ASTRONOaUCAL SOCIETIES OF LONDON, CORRESPONDENT OP THE ACADEMY OF 

NATURAL 8CIEMCE& OF PHILADELPHIA, &C. 8tC. &C. 



FOURTH EDITION, 

WITH NUMEROUS IMPROVEMENT& 



t 

LONDON : 

PRINTED FOR THOMAS TEGG, 73. CHEAPSIDE, 

AND 
R. GRIFFIK AND CO. GLASGOW. 

1831. 



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eif t or 

Francis A. Mar den, 
Nov York» 
3 Match, 1887- 



*j I 



Printad by Walker & Ordg. 
fidinburgta. 



TO 
THE RIGHT HONOURABLE 

THE EARL OF GLASGOW, 

BARON ROSS OF HAWKHEAD, 

&C. &C. &C. 

LORD LIEUTENANT OF AYRSHIRE. 



Mt Lord, 

When I inscribe this Volume to your Lordship, it is neither 
to offer the incense of adulation, which your virtues do not need, and 
your understanding would disdain ; nor to solicit the patronage of ex- 
alted rank to a Work, which in this age and nation must seek support by 
scientific value alone. The present dedication is merely an act of 
gratitude, as pure On my part, as your Lordship's condescension and 
kindness to me have been generous and unvarying. At my outset in 
life, your Lordship's distinguished favour cherished those studious pur- 
suits, which have since formed my chief pleasure and business ; and to 
your Lordship's hospitality I owe the elegant retirement, in which many 
of the following pages were written. Happy would it have been for 
their readers, could I have transfused into them a portion of that grace 
of diction, and elevation of sentiment, which I have so often been 
permitted to admire in your Lordship's family. 

I have the honour to be. 

My Lord, 

Your Lordship's most obedient 
Glasgow, 
November 7. 18S0. 

And very faithful Servant, 

ANDREW URE. 



ADVERTISEMENT 



TO THE 



FOURTH EDITION. 



I HAVE now the pleasure, for the fourth time, of offering my grateful 
acknowledgments to the Public for their effective patronage of this 
Dictionary. In submitting the third Edition to their perusal, I imagined 
that few alterations would be required should another impression of the 
Work be demanded within two or three years. But such has been the 
activity of the Chemical world, in supplying many desiderata of detail 
within this brief period, as already to furnish copious materials for 
addition and emendation. Accordingly I have felt it my duly to intro- 
duce into the following pages many articles entirely new, and to re- 
write, in whole or in part, several of those under old titles. The quan- 
tity of letter-press has been likewise increased, notwithstanding every 
effort of condensation ; so that the volume, from its compact style of 
typography, contains as much reading as would fill four ordinary oc- 
tavos. 

It has been my purpose to render the present Edition as exact and 
ample a transcript, as circumstances would allow, of the actual state of 
Chemical Science, and of its relations to Medicine, to the Phenomena 
of Nature, and to the Arts. With what success this design is executed, 
it is for the candour of my readers to decide. 



In the Press, and speedify will be Published, 

IN ONE LAROK VOLUME 8VOy 

A MANUAL OF ANALYTICAL CHEMISTRY, 

OOMFBIBDfG 

Instructions for Detecting the Presence, and Determining the Pk*o- 
portions of the Constituents of Chemical Compounds, including 
the Recent Discoveries and Improvements of Berzelius and other 
Analysts. 

BY HENRY ROSE, 

FROFESBOA OF CUEMIBTEY AT BEBLDT. 

Traii|rt(ite4 from the German by John Griffin^ 



INTRODUCTION. 



In this Introduction I shall present a General View of the objects 
of Chemistry, along with a scheme for converting the alphabetical ar- 
rangement adopted in this volume into a systematic order of study. 



The forms of matter are numberless, and subject to incessant change. 
Amid all this variety, which perplexes the common mind, the eye of 
science discerns a few unchangeable primary bodies, by whose recipro- 
cal actions and combinations this marvellous diversity and rotadon of 
existence are produced and maintained. These bodies, having resisted 
every attempt to resolve them into simpler forms of matter, are called 
umlecampcundedt and must be regarded in the present state of our know- 
ledge as esperimental dements. It is possible that the elements of nature 
are very dissimilar ; it is probable that they are altogether unknown ; 
and that they are so recondite, as for ever to elude the sagacity of hu- 
man research. 

The primary substances which can be subjected to measurement and 
weight are fif)y-two in number. To these, some chemists add the im- 
ponderable elements— light, heat, electricity, and magnetism. But their 
separate identity is not clearly ascertained. 

Of the fifty-two ponderable principles, four, possibly five, require a 
distinct collocation, from the marked peculiarity of their powers and 
properties. These are named Chlorine, Oxygen^ Iodine^ Fluorine^ and 
Bromine* These bodies display a pre-eminent activity of combination, 
an intense affinity for most of the other forty-seven bodies, which they 
corrode, penetrate, and dissolve ; or, by uniting with them, so impair their 
cohesive force, that they become friable, brittle, or soluble in water, 
. however dense, refractory and insoluble, they previously were. Such 
changes, for example, are operated on platinum, gold, silver, and iron, 
by the agency of chlorine, oxygen, or iodine. But the characteristic 
feature of these archeal elements is this, that when a compound consist- 
ing of one of them, and one of the other forty-seven more passive ele- 
ments, is exposed to voltaic electrization, the former is uniformly evol- 
ved at the positive or vitreo-electric pole, while the latter appears at the 
negative or resino-electric pole. 

The singular strength of their attractions for the other simple forms of 
matter is also manifested by the production of heat and light, or the 
phenomenon of combustion, at the instant of their mutual combination. 



viii INTRODUCTION. 

But this phenomenon is not characteristic ; for it is neither peculiar nor 
necessary to their action, and, therefore, cannot be made the basis of a 
logical arrangement. Combustion is vividly displayed in cases where 
none of these primary dissolvents is concerned. Thus certain metals 
combine with othen with such vehemence as to elicit light and heat ; 
and many of them, by their union with sulphur, even in vacuoy exhibit 
intense combustion. Potassium bums distinctly in cyanogen (carburet- 
ted azote), and splendidly in sulphuretted hydrogen. For other ex- 
amples to the same purpose, see Combustible and Combustion. 

And again, the phenomenon of flame does not necessarily accompany 
any of the actions of oxygen, chlorine, and iodine. Its production may 
be regulated at the pleasure of the chemist, and occurs merely when the 
mutual combination is rapidly effected. Thus chlorine or oxygen will 
unite with hydrogen, either silently and darkly, or with fiery explosion, 
as the operator shall direct. 

Since, therefore, the quality of exciting or sustaining combustion is 
not peculiar to these electro-positive elements ; since it is not indispens- 
able to their action on other substances, but adventitious and occasional^ 
we perceive the inaccuracy of that classification which sets these three 
or four bodies apart under the denomination o£ supporters of combustion i 
as if combustion could not be supported without them, and as if the 
support of combustion was their indefeasible attribute, the essential con- 
comitant of their action. On the contrary, every change which they 
can produce, by their imion with other elementary matter, may be 
effected without the phenomenon of combustion. See section 5th of 
article Combustion. 

The other forty-seven elementary bodies have, with the excepti<Ni of 
azote (the solitary incombustible), been grouped under the generic 
name of combustibles. But in reality combustion is independent of th^ 
agency of all these bodies, and therefore combustion may be produced 
Hxiithout any combustible* Can this absurdity form a basis of chemical 
classification ? The decomposition of euchlorine, as well as of the chlo- 
ride and iodide of azote, is accompanied with a tremendous energy of 
heat and light ; yet no combustible is present. The same examples are 
fatal to the theoretical part of Black's celebrated doctrine of latent heat. 
His facts are, however, invaluable, and not to be controverted, though 
the hypothetical thread used to connect them be finally severed. 

To the term combustible is naturally attached the idea of die body so 
named affording the heat and light. Of this position, it has been oflen 
remarked, that we have no evidence whatever. We know, on the other 
hand, that oxygen, the incombustible, could yield, from its latent stores, 
in Black's language, both the light and heat displayed in combustion ; 
for mere mechanical condensation of that gas, in a S3n*inge, causes their 
disengagement. A similar condensation of the combustible hydrogen 
occasions, I believe, the evolution of no light. From all these facts it 
is plain, that the above distinction is unphilosophical, and must be aban- 
doned. In truth, every insulated or simple body has such an appetency 



INTRODUCTION. ix 

to combine with, or is solicited with such attractive energy by* other 
fanns of matter, whether the actuating forces be electro-attractive or 
electrical) that the motion of the particles constituting the change, if 
sufficiently rapid, may always produce the phenomenon of combustion. 

Of the forty-seven electro-negative elements, forty-one are metallic, 
and six non-metallic. 

The latter group may be airanged into three pairs :«— 

Is^ The gaseous bodies, Htdrogen and Azote. 

2d, The fixed and infusible solids, Carbon and Boron. 

9d^ The fusible and volatile solids, Sulphur and Phosphorus. 

The forty-two metallic bodies are distinguishable by their habitudes 
with oxygen, into two great divisions, the Basifiable and Acidi- 
TiABLE metals. The former are thirty-five in number, the latter seven. 

Of the thirty-five metals, which yield by their union with oxygen 
salifiable bases, Uiree are convertible into alkalis, nine into earths, and 
twenty-three into ordinary metallic oxides. Some of the latter, how- 
ever, by a maximum dose of oxygen, seem to graduate into the acidi- 
fiable group, or at least cease to form salifiable bases. 

We shall now delineate a general chart of Chemistry, enumerating its 
various leading objects in a somewhat tabular form, and pointing out 
Uieir most important relations, so that the readers of this Dictionary may 
have it in their power to study its contents in a systematic order. 

CHEMISTRY 

is the science which treats of the specific differences in the nature of 
bodies, and the permanent changes of constitution to which their mutual 
actions give rise. 

This ^versity in the nature of bodies is derived either from the 
AGGREGATION or COMPOSITION of their integrant particles. The state 
of aggregation seems to depend on the relation between the cohesive 
attraction of these integrant particles, and the antagonizing force of heat. 
Hence the three general forms of s(did, liquidy and gaseom, under one 
or other of which every species of material being may be classed. 

For instruction on these general forms of matter, the student ought to 
read, Ist, The early part of the article Attraction ; 2d, Crystalli- 
zation ; dd, That part of Caloric entitled, <^ Of the change of statg 
produced in bodies by caloric, independent of change of composition." 
He may then peruse the introductory part of the article Gas, and 
Balance, and Laboratory. He will now be sufficiently prepared 
for the study of the rest of the article Caloric, as well as that of its 
correlative subjects. Temperature, Thermometer, Evaporation, 
Congelation, Cryophorus, Dew, and Climate. The order now pre- 
scribed will be found convenient. In the article Caloric there are a 
few discussions which the beginner may perhaps find somewhat difficult. 
These he may pass over at the first reading, and resume their considera- 
tion in the sequel. After Caloric he may peruse Light, and the first 
three sections of Electricity. 



I 

I X INTRODUCTION. 



The article Combustion will be most advantageously examined, after 
he has become acquainted with some of the diversities of Composition ; 
viz. with the four electro-positive dissolvents, oxygen, chlorine, bromine, 
and iodine ; and the six non-metallic electro-negative elements, hydro- 
gen, azote, carbon, boron, sulphur, and phosphorus. Let him begin 
with oxygen^ and then peruse, for the sake of connexion, hydrogen and 
toaUr* Should he wish to know how the specific gravity of gaseous 
matter is ascertained, he may consult the fourth section of the article 
Gas. 

The next subject to which he should direct his attention is Chlo- 
rine ; on which he will meet with ample details in the present Work. 
This article will bear a second perusal. It describes a series of the 
most splendid efforts ever made by the sagacity of man, to unfold the 
chemical mysteries of nature. In connexion with it, he may read the 
articles Chlorous and Chloric Oxides, or the protoxide and deut- 
oxide of Chlorine. Let him next study the copious articles Bromine 
and Iodine, from beginning to end. 

Carbon, boron, sulphur, phosphorus, and azote, must now come under 
review. Related closely with the first, he will study the carbonous oxide, 
carburetted and subcarburetted hydrogen. What is known of the element 
boron will be speedily learned ; and he may then enter on the examina- 
tion of sulphury sulphuretted hydrogen, and carburet of sulphur. PhoS' 
phorus and phosphuretted hydrogen, with nitrogen or cut^ey and its oxides 
and chlorides, will form the conclusion of the first division of chemical 
study, which relates to the elements of most general interest and acti- 
vity. The general articles Combustible, Combustion, and Safe-Lamp, 
may now be read with advantage ; as well as the remainder of the ar- 
ticle Attraction, which treats of affinity. 

Since in the present work the alkaline and earthy salts are annexed to 
their respective acids, it will be proper, before commencing the study of 
the latter, to become acquainted with the alkaline and earthy bases. 

The order of reading may therefore be the following : first, The ge- 
neral article alkali, then potash and potassium, soda and sodium, lithia 
and ammonia. Next, the general article earth ; afterwards calcium and 
lime, barium and baryta, strontia, magnesia^ alumina^ silica, ^udna, zir- 
conia, yttria, and thorina. 

Let him now peruse the general articles acid and salt ; and then the 
non^metallic oxygen acids, with their subjoined salts, in the following 
order : — sulphuric, sulphurous ; hyposulphurous, and hyposulphuric ; phos- 
phoric, phosphorous, and hypophosphorous ; carbonic and chlorocarbonous / 
boracic ; and, lastly, the nitric and nitrous. The others may be studied 
conveniently with the hydrogen group. The order of perusing them 
may be, the muriatic (hydrochloric of M. Gay Lussac), chloric, and 
perchloric; the hydriodic, iodic, and chloriodic; theJiuoric^uoboriCf and 
Jluosilicic ; the prussic (hydrocyanic of M. Gay Lussac), ferroprussic, 
chloraprtissic, and sulphuroprussic. The hydrosulphurous and hydroteU 
lurous are discussed in this Dictionary, under the names of sulphuretted 



INTRODUCTION. xi 

kydrogeny and idluretted hydrogen. These compound bodies possess 
add powers, as well perhaps as arsenuretted hydrogen. It would be 
advisable to peruse the article cyanogen either before or immediately 
aAer prussic add. 

As to the vegetable and animal acids, they may be read either in 
their alphabetical order, or in any other which the student or his teacher 
shall think fit. 

The metallic acids fall naturally under metallic chemistry; on the 
study of which I have nothing to add to the remarks contained in the 
general article Metal. Along with each metal in its alphabetical 
place, its native state, or oresy may be studied. See Ores. 

The chemistry of organized matter may be methodically examined 
by perusing, first of all, the article vegetable kingdom, with the various 
products of vegetation there enumerated : and then the article animal 
Ungdomy with the subordinate animal products and adipocere. 

The article analysis may now be consulted; then mineral waters ; 
egmoaknis (chemical), and analysis of ores. 

The mineralogical department should be commenced with the general 
articles mineralogy and crystallography ; afler which the different species 
and varieties may be examined under their respective titles. The enu- 
meration of the genera of M. Mohs, given in the first article, wiU guide 
the student to a considerable extent in their methodical consideration. 
Belonging to mineralogy, are the subjects UowpipCy geology, with its 
subordinate rocks, ores, and meteorolite. 

The medical student may read with advantage the articles acid (ar- 
semous), antimony, bile, blood, calculus (urinary), the sequel of copper, 
digestion, gaU^skmes, galvanism, intestinal concretion, lead, mercury, poi' 
sons, respiration, urine, tgc. 

The agriculturist will find details not unworthy of his attention, under 
the articles absorbent, analysis of soils, carbonate, lime, manure, and soils. 

Among the discussions interesting to manufacturers are, acetic and 
other adds, alcohol, alum, ammonia, beer, bleaching, bread, caloric, chloride 
of lime, coal, coal-gas, distillation, dydng, ether. Jot, fermentation, glass, 
ink, iron, ores, potash, pottery, salt, soap, soda, steel, sugar, tanning, Sfc, 

The general reader will find, it is hoped, instruction, blended with en- 
tertainment, in the articles aerostation, air, dimate, combustion, congela- 
iion, dew, dectridty, equivalents, galvanism, geology, light, meteorolite, 
rain, and several other articles formerly noticed. 



n 



ADDITIONS AND CORRECTIONS. 



GUNPOWDER. On making inquiry 
at the Royal Manufacture of Waltfaam AIk- 
bey, I learn that Mr Coleman was mistaken 
in stating tliat the gunpowder of that esta- 
blishment had been increased one-third in 
strength by tlie introduction of cylinder diar- 
coal, instead of that formerly made in pits. 

MERCURY. Under this arUcle, p. 614. 
I have spoken of the use of fulminating mer- 
cury as a match-powder for the percussion 
caps of detonating muskets. In the full re- 
port of the French experiments given in the 
Bulletin det Sciences MHitaires for January 
1830, I find it stated, that six parts of or- 
dinary gunpowder must be ground up with 



ten paiis of the fulminating mercury, pre- 
viously tritumted with water on a mart>le 
slab by a wooden muller. Each cap-match 
contains, it is said, Hth grain of fulminat- 
ing mercury, with 6-fOths of that weight of 
cannon powder. But some of the best matdi 
powders made in France are much lighter, 
and do not weigh altogether above S-Sds of 
a grain. 

PHOSPHORUS. F^ 07a middleof 
first column. The sentence, " It is the 
bichloride of phosphorus," has been retained 
by an oversight fVom the preceding edition. 
It ought to be cancelled. 



DICTIONARY 



OF 



CHEMISTRY 



ABS 

AdRAZITE, ZEAGOKITE, or OIS- 
MONDINE. A mineni wUch occun 
in serai-globular masses, and in octahedral 
crystak with a square basev Colour greyish- 
white, aomeciines with a tinge of blue. Yields 
lo the nail, but oocasionaUy hard enough to 
acntch glass. Brittle^ Fracture conchoidal. 
Translucent or transparent. Constituents: 
slica 4t.4 ; lime 46.6 ; alumina 2.5 ; mag- 
nesia L5 ; oxide ot iron 2.5. Reduced by 
acids to a jelly, without effenresccnce. Loses 
its lustre, and becomes friable before the blow- 
pipe. It is found in the cavities of volcanic 
rocks, with calcareous spar, at Capo di Bove 
near Rome.— PAi2/i^s* Minerahgy. 

ABSORBENT. An epithet introduced 
into chemistry by the physicians, to designate 
such earthy substances as seeaoed to check 
dSarrhoea, by the mere absorption of the re- 
dundant liquids. In this sense it is obsolete 
and unfounded. The facalty of withdrawing 
moistBre from the air is not confined to sub- 
stances which unite with water in every pro- 
portion, as the strong adds, dry alkalis, alka- 
line earths, and deliquescent s^ts, but is pos- 
sessed by insoluble and apparently inert bodies, 
in various degrees of force. Hence the term 
Absorbent merits a place in chemical nomen- 
clature. 

The substance whose absorbent power is 
to be examined, after tborou^ desiccation 
before a fire, is immediately transferred into 
a phial, furnished with a well ground stopper. 
When it is cooled, a portion of it is put into 
a large wid^mouthed bottle, where it u close- 
ly confined Ibr some time^ A delicate hygro- 
meter being then introduced, indicates on its 
scale the dryness produced in the enclosed air, 
which should have been previously brought to 
the point of extreme humidity, by suspending 



ABS 

a moistened rag within the bottle. The fol- 
lowing table exhibits the results of experi- 
ments made by Fhifessor Leslie :— 

Alumina causes a dryness of 84 degrees. 
Carbonate of magnesia, - 75 
Carbonate of lime, -^ 70 

Silica, ^ . . 40 

Carbonate of baryta, - 32 
Carbonate of strontia, - 23 
Pipeclay, ... 85 
Greenstone^ or trap in powder, 80 
Shelly sea sand, . . 70 
Clay indurated by toirefilction, 35 
Clay strongly ignited, - 8 
Greenstone ignited, - 23 

Quarts do. - ^19 

Decomposed greenstone, 86 

Greenstone resolved into soil, 92 
Garden mould, - - 95 

The more a soil is eomminnted by labour and 
^vegetation, the greater is its absorbent power. 
This ingenious philosopher infers, that the 
fertility of soils depends chiefly on their dis- 
position to imbibe moisture; and illustrates 
this idea by recent and by disintegrated lava. 
May not the finely divided state most pene- 
trable by the delicate fibres of plants, derive 
its superior power of acting on atmospherical 
vapour from the augmentation of its surftce 
or the multiplication of the points of contact? 
In similar dreumstances 100 gr. of the 
following organic substances absorb the fol- 
lowing quantities of moisture : Ivory 7 gr. 
boxwood 14, down 16, wool 18, beech 2^ 
Charcoal, and other porous solids of a fibrous 
texture, have the fiiculty of absorbing gases 
in a remarkable degree;— for an account of 
M. de Saussure*s excellent experiments on 

A 



ACH S ACID& 

which subject, see the article Gas in this Die- from the ▼arious colours of light, are called 

tionary. — LedU on Heat and JHoisture. achromatic telescopes. 

ABSORPTION. The passage of a gas, ACID& The most important dass of 

or Tapour, into a liquid or solid substance ; or chemical compounds. In the generalization 

of a liquid into the pores of a solid. of facts presented by Lavoisier and the 



ACANTICONE. See Fistacite. dated French chemists, it was the leading 
' ACERATESb The acer campestre, or doctrine that adds resulted from the union of 
common maple, yields a milky sweetish sap, a peculiar combustible base called the radical, 
containing a salt with basis of Ume, possessed, with a common prindple technically called 
according to Scherer, of peculiar properties, oxygen, or the addifier. Thb general pod- 
It is white, semitransparent, not altered by tlon was founded chiefly on the phenomena 
the air, and soluble in nearly 100 parts of exhibited in the formation and decomposition 
cold, or 50 of bdling water. of sulphuric, carbonic, phosphoric, and nitric 

ACERIC ACID. See Acm (AcEUc). adds; and was extended by a plausible ana- 

ACESCENT. Substances which become logy to other adds whose radicals were un- 

sour spontaneously, aa vegetable and animal known. 

juices, or infusions. The suddenness with ** 1 have already shown," says Lavoisier^ 

which this change is effected during a thunder " that phosphorus is changed by combustion 

storm, even in corked bottles, has not been into an extremely light, white, ^flaky matter, 

accounted for. In morbid states of the sto- Its properties are likewise entirely altered 

mach, also, it proceeds with astonishing ra- by this transformation : from bdng insoluble 

pidity. It is counteracted by bitters, antadds, in water, it becomes not only soluble, but so 

and purgatives. gi'eedy of mdsture as to attract ttte humidity 

ACETATES. Salts formed by the com- of the air with astonishing rapidity. By thia 

bination of acetic add with alkalis, earths, means it is converted into a liquid, consider- 

and metallic oxides. See Acm (Acetic). ably mbre denser and of more specific gravity 

ACETIC ACID. See Acid (Acetic). than water. In the stale of phosphorus before 

ACETOMETER. An instrument for combustion, it had scarcely any sensible taste; 
estimating the strength of vinegars. It is by its union with oxygen, it acquires an ex- 
described under Agio (Acetic). tremely sharp and sour taste : in a word, from 

ACETOUS. Of or belonging to vinegar, one of the class of combustible bodies, it ia 

See Acid (Acetic). changed into an incombustible substance, and 

A CHI RITE. Emerald Malachite ; a mi- becomes one of those bodies called acids, 
neial consisting of oxide of copper, carbonate " This property of a combustible substance* 

of lime, silica and water. It dismlves in glass to be converted into an add by the addition 

of borax, and imparts a green polour to it. of oxygen, we shall presently find belongs to 

It is soluble vrithout effervescence in muriatic a great number, of bodies. Wherefore strict 

add. logic requires that we should adopt a com- 

ACHMIT. A mineral first distinguished mon term for indicating all those operationa 

by Bergmdster Strom. It has a brownish- which produce analogous results. This is the 

black or reddish-brown colour, is spotted^ true way to simplify the study of sdenoe, as it 

greyish-green in the fracture, externally of a would be quite impossible to bear all its spe^ 

glassy lustre, and in the transverse fracture cific details in the memory if they were not 

glimmering. Translucent in small fragments, classically arranged. For this reason we shall 

It has four cleavages, two of which are parallel distinguish the conversion of phosphorus into 

to the sides of an oblique four-sided prism, an acid by its union with oxygen, and in ge- 

and the other two^ less obvious, are parallel nend every combination of oxygen with a oom- 

to the truncations of the acute lateral edges.* bustible substance^ by the term oxygenation : 

The fracture is small grained. Specific gra- from this I shall adopt the verb to oxygenate, 

vity 5*24h Hardness such as to scratch glass, and of consequence shall say, that in oxyge- 

It is likewise crystallised in obh'que four-sided nating phosphorus, we convert it into an add. 
prisms, with truncated lateral edges, and very *' Sulphur also, in burning, absorbs oxygen 

sharp fbur-fiided terminal faces, the edges of gas ; the resulting add is considerably heavier 

which correspond with the lateral edges of the than the sulphur burnt; its weight is equal 

oblique prism. The sides are channelled in to the sum of the wdghts of the sulphur 

the direction of their length. According to which has bcgm burnt, and of the oxygen ab- 

Berzelius this mineral contains— silica 55.25, sorbed ; and, lastly, this add is weighty, in- 

peroxide of iron dl.25» protoxide of manga- combustible^ and misdble with water in all 

nese 1.08, lime 0.72, soda 10.40, oxide of proportions. 

titanium a tracer He considers it as a bisili- ** I might multiply these experiments, and 

cate of soda, combined with a bisilicate of show, by a numerous succession of facts, that 

iron. all adds are formed by the combustion of 

ACHROMATIC Tdescopes formed of certain substances ; but I am prevented from 

a combination of lenses, which in a great doing so in this place by the plan which I 

neasura correct the optical aberration arising have laid down, of proceeding only from fact» 



ACIDS 



3 



IN GENERAL. 



•iMfldy necrtained to each aa are unknown^ 
aod of diawing my eiamplea only from cir- 
CfonBtaQoea already explained. In the mean 
time^ howerer, the ezampleB above dted may 
aulBce for giving a clear and accurate con- 
cqitioa of the manner in which acids are 
lonned. By these it may be clearly seen that 
Oixygen is an dement common to them all, 
and which constitutes or produces their aci- 
dity; and that they differ from each other 
according to the seteral natures of the oxy- 
genated or acidified substances. We must, 
th cfe fo re^ in erory add carefully distinguish 
ba t w e eu the addifiable base, which M. de 
Morreao calls the radical, and the addilying 
pfiadple or oxygen." Elements, p. 115.— > 
** AltixNigh we have not yet been able either 
to compose or toilecompound this add of sea 
salt, we cannot have the smallest doubt that 
i^ like all other adds, is composed by the 
vaion of oxygen with an addifiable base^ 
We bavcy therefore, called this unknown sub- 
stance the muriatic base^ or muriatic radicaL'* 
P. 122: 5th Edition. 

BerthoUet*B sound discrimination led him 
to maintain that Layoisier had given too much 
Islitude to the idea of oxygen bdng the uni- 
venal addifying prindple. *' In fact,*' says 
be^ " it is carrying the limits of analogy too 
lar to infer, that all addity, even that of the 
mvriatic, fluoric, and borsdc adds, arises 
from oxygen, because it gives addity to a 
great number of substances. Sulphuretted 
hydrogen, which really possesses the proper- 
ties of an add, proves directly that addity 
is not in all cases owing to oxygen, lliere 
is no better foundation for concluding that 
hydrogen is the prindple of alkalinity, not 
only in the alkalis properly so called, but 
also in magnesia, lixne, strontia, and baryta, 
because ammonia appears to owe its alkalinity 
to hydrogen. 

** These ooosiderations prove that oxygen 
may ba regarded as the most usual prindple 
of addity, but that this spedes of affinity for 
the alkalis may bdong to substances which 
do not contain oxygen; that we most not^ 
theiefore, always infor, from the addity of a 
fobslanee^ that it contdns oxygen, although 
this may be an inducement to suspect its ex- 
iftenoe in it: still less should we conclude, 
bt^«f» a substance contains oxygen, that it 
most have add properties; on the contrary, 
the acidity of an oxygenated substance shows 
that the oxygen has only experienced an in^- 
oompleie saturation in it, since its properties 
remain predominant.'* 

Amid the just views which prevade the 
cariy part of this quotation from BertboUet, 
it is curious to remark the solecism with 
which it terminates. For after maintdning 
that acidity may eiist independent of oxygen, 
and that the presence of oxygen does not n&- 
ily constitute acidity, he concludes by 



considering addity as the attribute of unsatu- 
rated oxygen. 

This unwarrantable generalization of the 
French chemists concerning oxygen, which 
had succeeded Stahl's equally unwarrantable 
generalization of a common prindple of oon^ 
bustibility in all combustible bodies, was first 
experimentally combated by Sir H. Davy, in 
a series of admirable dissertations published 
in the Philosophical Transactions. 

His first train of experiments was instituted 
with the riew of operating by voltaic electridty 
on muriatic and other adds freed from water. 
Substances which are now known by the names 
of chlorides of phosphorus and tin, but which 
he then supposed to contain dry muriatic acid, 
led him to imagine that intimately combined 
water was the real acidifying prindple, since 
add properties were immediately developed in 
the above substances by the addition of that 
fluid, though previously they exhibited no add 
powers. In July 1810, however, he advanced 
those celebrated views concerning acidification, 
which, in the opinion of the best judges, dis- 
play an unrivalled power of sdentific resesrch. 
The conclusions to which these led him were 
incompatible with the general hypothesis of 
Lavoisier. He demonstrated that oxymuri- 
atic add is, as far as our knowledge extends^ 
a timple substance, which may be classed in 
the same order of natural bodies as oxygen 
gas, bdng determined like oxygen to the 
positive surface in voltuc combinations, and 
like oxygen combining with inflammable sul^ 
stances, produdng heat and light. The com* 
binations of ox3rnmriatic add with inflanh- 
mable bodies were shown to be analogous to 
oxides and adds in tfadr properties and powen 
of combination, but to differ from them in 
being for the most part decomposable by 
water ; and finally, that oxymuriatic add has 
a stronger attraction for most inflammable 
bodies than oiygen. His preceding decom- 
position of the alkalis and earths baring 
evinced the absurdity of that nomenclature 
which gives to the general' and essential con- 
stituent of alkaline nature^ the term oxygen or 
acidifier ; his new discovery of the simplicity of 
oxymuriatic add showed the theoretical sys- 
tem of chemical language to be equally vicious 
in another respect Hence this philosopher 
most judidously discarded the i^ipdlation 
oxymuriatic add, and introduced in its place 
the name chlorine, which merely indicates an 
obvious and permanent character of the sul^ 
stance, its greenish-ydlow colour. The more 
recent investigations of chemists on fluoric, 
hydriodic, and hydrocyanic adds, have brought 
powerful analogies in support of the chloiidic 
theory, by showing that hydrogen done can 
convert certdn undecompounded bases into 
adds wdl characterized, without the dd of 
oxygen. Dr Murray indeed endeavoured to 
revive and new-model the early opinion of Sir 



ACIDS 4 IN GENERAL. 

H. Davj, eoncerning the necessity of the pre- quired tban from the action of either tdone*. 
sence of water, or its elements, to the consti- Sulphur affords a striking example of this» 
tution of acids. He conceiYed that many adds With hydrogen it forms a weak acid. With 
are ternary compounds of a radical with oxy- oxygen it also forms an add, which, though 
gen and hydrogen ; but that the two latter in- of superior energy, still does not display 
gredients do not necessarily exist in them in much power. With hydrogen and oxygen 
the state of water. Oil of Yitriol, for instance, it seems to receive the acidifying influence 
in this view, instead of consisting of 81.5 real of both, and its addity b proportionally ex- 
add, and 18.5 water, in 100 parts, maybe alted. 

regarded as a compound of 32.6 sulphur -f- ** Nitrogen, with hydrogen, forms a com- 

65.2 oxygen -{-2.2 hydrogen. Wlien it is pound altogether destitute of addity, and 

saturated with an alkaline base, and exposed possessed even of qualities the reverse. With 

to heat, the hydrogen unites to its equivalent oxygen, in two definite proportions, it forma 

quantity of oxygen, to form water, which ev»- oxides ; and it is doubtful if, in any propor- 

porates, and the remaining oxygen and the sul- tion, it can establish with oxygen an insulated 

phur combine with the base. But when the add. But with oxygen and hydrogen in union 

add is nude to act on a metal, the oxygen it forms nitric add, a compound more per- 

partly uniteato it, and hydrogen alone escapes, manent, and of energetic action. '* 

** Nitric add, in its highest state of con- It is needless to give at more detail Dr 

centration, is not a definite compound of real Murray's speculations, which, supposing them 

add, with about a fourth of its wdght of plausible in a theoretical point of view, seem 

water, but a ternary compound of nitrogen, barren in practice. It is sufficiently singular, 

oxygen, and hydrogen. Phosphoric acid is that, in an attempt to avoid the transformap* 

tk triple compound of phosphorus, oxygen, tions, which, on his notion of the chloridic 

and hydrogen ; and phosphorous add is the theory, a little moisture operates on common 

proper binary compound of phosphorus and salt, instantly changing it from chlorine and 

oxygen. The oxalic, tartaric, and other reg&- sodium into muriatic acid and soda, Dr 

table adds, are admitted to be ternary com- Murray should have actually multiplied, with 

pounds of carbon, oxygen, and hydrogen ; and one hand, the very difficulties which he had 

are therefore in strict conformity to the doe- laboured, vrith the other, to remove, 
trine now illustrated. He thinks it doubtful if nitrogen and oxy- 

** A relation of the elements of bodies to gen can alone form an insulated add. Hy- 

acidity is thus discovered different fVom what drogen he concdves essential to its energetic 

has hitlierto been proposed. When a series action. What, we may ask then, exists in 

of compounck exist, which have certain com- dry nitre^ which contains no hydrogen ? Is 

roon characteristic properties, and when these it nitric add, or merely two of its elemental 

compounds all contain a common element, in want of a little water to furnish the re- 

vre conclude, with justice, that tliese proper- quisite hydrogen ? The same questions may 

ties are derived more peculiarly from the ao- be asked relative to the sulphate of potashi 

ti6n of this elepient. On this ground La- Since he conceives hydrogen necessary to* 

voider inferred, by an ample induction, that communicate full force to sulphuric and ni- 

oxygen is a prindple of acidity. BerthoUet trie adds, the moment they lose thdr water 

brought into riew the conclusion, that it is they should lose thdr saturating power, and 

not exdusively so, from the examples of prus- become incapable of retaining caustic potasli 

sic add and sulphuretted hydrogen. In tlie in a neutral state. Out of tliis dilemma he 

latter, addity appeared to be produced by the may indeed try to escape, by saying, that 

action of hydrogen. Hie discovery by Gay moisture or hydrogen is equally essential to- 

Lussac, of the compound radical cyanogen, alkaline strength, and that therefcn^ the same 

and its conversion into pnisdc add by the desiccation or de-hydrogenation which impairs 

addition of hydrogen, confirmed this conclu- the add power, impairs also that of its aJka- 

sion; and the discovery of the relations of line antagonist The result must evidently 

iodine still further established it. And now, be, that, in a saKne hydrate or solution, we 

if the preceding views are just, the system have the redprocal attractions of a strong acid 

must be still further modified. While each and alkali, while, in a dry salt, the attractive 

of these conclusions is just to a certain ex- forces are those of relatively feeble bodies* 

tent, each of them requires to be limited in On this hypothesis, the difference ought to be 

some of the cases to which they are applied ; great between dry and moistened sulphate oT 

and while addity is sometimes exclusively potash. Carbonic add he admits to be desti- 

connected vrith oxygen, sometimes with hy- tute of hydrogen ; yet its saturating power is 

drogen, the prindple must also be admitted, very conspicuous in neutralizing dry lime, 

that it is more frequently the result of thdr Again, oxalic add, by the last analysis of 

combined operation. Bmelkis^ as weU as my own, contains no 

** There appears even sufficient reason to hydrogen. It differs from the auhonic only in 

infer, that, from the united action of these the proportion of its two constituents. And 

elements, a higher degree of acidity is ac- oxalic acid is appealed to by Dr Murray as a 



ACIDS . 5 IN GENERAL. 

proof of the superior acidity iMitowed by & They unite in definite proportions with 

hydrogen. the alkalis,' earths, and metallic oxides, and 

On what grounds he decides carbonic to be form the important class of Salts. This may 
« ieebler acid than oxalic, it is difficult to be reckoned their characteristic and indis- 
aee. By Bertbollet*s test of addity, the pensable property. The powers of the dif- 
former is more energetic than the latter in ferent acids were originally estimated by their 
4fae pvoportion of 100 to about 56 ; for these relative causticity and sourness, afterwards 
numbers are inversely as the quantity of each by the scale of their attractive force towards 
requiate to saturate a given base. If he be any particular base, and next by the quantity 
indined to reject this rule^ and appeal to the of the base which they could respectively 
decompadtion of the carbonates by oxalic neutralise. But Berthollet proposed the 
add, as a criterion of relative add power, let converse of this last criterion as the measure 
Its adduce hia mt^ commentary on the sta- of their powers. ** The power with which 
tical affinities of Berthollet, where he ascribes they can exerdse thdr addity," he estimates 
such changes, noW|p a superior attraction in ** by the quantity of each of the adds which 
the decomposing soostanoe, but to the elastic is required to produce the same effect, viz. to 
tendency of that which is evolved. Ammonia saturate a given quantity of the same alkali." 
separates magnena fifxim its muriatic solution It is therefore the capadty for saturation of 
at coDomon temperatures; at the boiling beat each add, which, in ascertaining its addity, 
of water, magnesia separates ammonia. Car- according to him, gives the comparative force 
bonate of ammonia, at temperatures under of the affinity to which it is owing. Hence 
230^, predpitates carbonate of lime from the he infers, that the affinity of the difierent 
muriate ; at higher temperatures, the inverse adds for an alkaline base, is in the inverse 
decomposition takes place with the same in- ratio of the ponderable quantity of each of 
gredients. If the oxalic be a more energetic them which is necessary to neutralise an equal 
add than the carbonic, or mnk higher in the quantity of the same slkaline base. An add 
scale of addity, then, on adding to a given is, therefore, in this view, the more powerful* 
weight of liquid muriate of lime a mixture of when an equal weight can saturate a greater 
oxalate and carbonate of ammonia, each in quantity of an alkalL Hence, all those sub- 
equivalent quantity to the calcareous salt, stances which can saturate the alkalis, and 
oxalate of lime ought alone to be separated, cause their properties to disappear, ought to 
It will be found, on the contrary, by the test be classed among the adds ; in like manner, 
of aoedc add, that as much carbonate of lime among the alkalis should be placed all those 
will predpitate as is suffident to unsettle these which, by their union, can saturate addity. 
speculations. And the capadty for saturation being the 

Finally, dry nitre^ and dry sulphate of measure of this property, it should be em- 
potash, are placed, by this supposition, in as ployed to form a scale of the comparative 
mysterious a predicament as dry muriate of power of alkalis as well as that of adds. 
soda in the chloridic theory. Deprived of However plausible, a priori, the opinion of 
hydrogen, thdr add and alkali are enfeebled this illustrious philosopher may be, that the 
or totally changed. With a little water, both smaller the quantity of an add or alkali re- 
instantly recruit thdr powers. In a word, quired to saturate a given quantity of its an- 
the solid sulphuric add of Nordhausen, and tagonist prindple, the higher should it rank 
the dry potash of potassium, are alone suf- in the scale of power and affinity, it will not, 
fident to subvert this whole hypothesis of by- however, accord with chemical phenomena, 
drogenation. 100 parts of nitric add are saturated by about 

We shall introduce^ under the head of 36^ of magnesia, and 52^ of lime. Hence, 

alkali, some analogous speculations by Dr by Berthollet's rule, the powers of these earths 

Murray on the influence of the elements of ought to be inversely as thdr quantities, viz. 

water on that ckus of bodies. Edin, PhiL 1,1 ^ . . » 

Trams. voLviiL part 2d. 36i 52i' ^® ^ ^"^ ^^^^^ *^^ 

takes place, for lime separates magnesia from 

After these observations on the nature of nitric acid. And in the present example, the 

addity, we shall now state the general proper- difference of effect cannot be imputed to the 

ties of the adds. difference of force with which the substances 

1. The taste of these bodies is for the most tend to assume the solid state. 

part sour, as thdr name denotes; and in the We Iwve therefore at present no single 

stronger spedes it is acnd and corrosive. acidifying prindple, nor absolute criterion of 

2. They generally combine with water in the scale of power among the different adds ; 
every proportion, vrith a condensation of vo- nor is the want of this of great importance, 
lume and evolution of heat Experiment furnishes us with the order of de- 

a With a few exceptions they are vola- composition of one addo-alkaUne compound 

tilixed or decomposed at a moderate heat by another add, whether alone, or aided by 

4w They usoaUy change the purple colours temperature; and this is all which practical 

of vegetables to a bright red. chemistry seems to require. 



ACIDS 



IN GENERAL. 



Before entering on the particular adds, 
we shall here describe the genei^ process by 
which M. Thenard has lately succeeded in 
communicating to many of them apparently 
a surcbaige of oxygen, and thus producing a 
supposed new class of bodies, the oxygenized 
acids, which are, in reality, combinations 
of the ordinary acids with oxygenized water, 
or with the deutoxide of hydrogen. The 
first notice of these new compounds ap- 
peared in the jtnn, de Chimie et Phynque, 
viii. 306, for July 1818; since which time 
several additional communications of a very 
interesting nature have been made by the 
'same celebrated chemist He has likewise 
formed a compound of water with oxygen, in 
which tlie proportion of the latter principle is 
doubled, or 616 times its volume is added. 
The methods of oxygenizing the liquid adds 
and water agree in this, ^at deutoxide of 
barium is formed first of all, from which the 
above liquids, by a subsequent process, derive 
their oxygen. He prescribes the following 
precautions, without which success will be 
only partial :— 

1. Nitrate of baryta should first be ob» 
tained perfectly pure, and, above all, free 
from iron and manganese. The most certain 
means of procuring it is to dissolve the ni- 
trate in water, to lutd to the solution a small 
excess of baiyta water, to filter and cry»- 
tallise. % The pure nitrate is to be decom- 
posed by heat. This ought not to be done 
in a common earthenware retort, because it 
contains too much of the oxides of iron and 
manganese, but in a perfectly white porcelain 
Ktort Four or five pounds of nitrate of 
baryta may be decompcsed at once, and the 
process wUl require about three hours, The 
baryta thus procured will contain a consider- 
able qoanti^ of silex and alumina; but it 
will have only very minute traces of manga^ 
nese and iron, a circumstance of essential 
importance. 3. The baryta, divided by a 
knife into pieces as large as the end of the 
thumb, should then be placed in a luted tube 
of glass. This tube should be long, and 
laige enough to contain from 2^ to 3} lbs. 
It is to be surrounded with fire, and heated 
to dull redness, and then a current of dry 
oxygen gas is to be passed through it. How- 
ever rapid the current, the gas is completely 
absorbed; so that when it passes by the 
small tube, which ought to terminate the 
laiger one, it may be conclqded that the 
deutoxide of barium is completed. It is, 
however, right to continue the current for 
seven or eight minutes more. Then the tube 
bdng nearly cold, the deutoxide, which is of 
a light grey colour, is taken out, and pre- 
sennBd in stoppered bottles. When this i« 
moistened it fiills to powder, without much 
increase of temperature. If in this state it 
be mixed with seven or eight times its weight 
of water, and a dilute acid be poured in, it 



diflflolves gnulually by agitation, without the 
evolution of any gas. The solution is neutral, 
or has no action on turnsole or turmeric 
When we add to this solution the requisite 
quanti^ of sulphuric add, a copious preci- 
pitate of baryta fidls, and the filtered liquor 
is merely water, heading in solution the oxy- 
genized add, or deutoxide of hydrogen, com* 
bined with the add itself. 

The class of adds has been distributed into 
three orders, according as they are derived 
from the mineral, the vegetable, or the animal 
kingdom. But a more apedic distribution 
u now requisite. They have also been ar- 
ranged into those which jbave a single^ and 
those which have a compound basis or radicaL 
But this arrangement is not only vague, but 
liable in other respects to considerable objec- 
tions. The chief advantage of a dasstfication 
is to give general views to beginners in the 
study, by grouping together such substances 
as have analogous properties or composition. 
These objects, it is hoped, will be tolerably 
wdl attained by the following divisions and 
subdivisions. 

Division Ist, Adds from inorganic nature^ 
or which are procurable without having re- 
course to animal or v^etable products. 

Division 2d, Adds elaborated by means of 
organization. 

Hie first group is subdivided into three 
families : 1st, Oxygen acids ; 2d, Hydrogen 
adds ; 3d, Adds destitute of both these sup* 
posed addifiers. 



Family 1st- 
Section Ist, 

1. Boracic 

2. Bromic. 

3. Carbonic. 

4. Chloric 

5. Perdilcmc 

6. ChlorocariMnic 

7. lodous. 

8. Nitrous. 

9. Hyponitric. 

10. Nitric 

11. Hyponitrous. 



-Oxygen adds. 
Non-metallic 

12. Iodic 

13. lodo-sulphuric 
14^ Hypophosphoroua* 

15. Phosphorous. 

16. Phosphatic 

17. Phosphoric 

18. Hyposulphuroua. 

19. Sulphurous. 

20. Hyposulphuric 

21. Sulphuric 

22. Cyanic 



Section 2d, Oxygen acids^Metalh'c 

1. Arsenic 8. Manganesous. 

2. Arsenious. 9. Molybdic 

3. Antimonious. 10. Molybdous. 
^ Antimonic 11. Selenic 

5. Chromic 12. Selenious. 

6. Columbic 13. Titanic 
7r Manganesic 14. Tungstic 

Family 2d«— -Hydrogen adds. 

1. Fluoric 6. Hydrobromic 

2. Hydriodic 7. Hydroselenic 

3. Hydrochloric, or 8^ Hydrocyanic 

Muriatic. 9. Hydrosulphurous, 

4. Ferrocyanic 10. Hydrotellurous. 

5. Fluotitanic 11. Sulphocyanic. 



ACID 



ACETIC. 



Vmadty SdL-^^Adds withoot oiygen or 
hjdrogen. 
I. eUcuriodic. a Fluoboric. 

2L^ Chkrocyaiiic. 4. Fluodlicic. 

Diviaion 2d.—- Acids of oiganic origin. 

1. Abifltic 35w MaUc 

2. Aceric 36. Meoonic. 

3. Acetic. 37. Meoispermic? 
4k ^AJoetic. 38. Margaric 

& Ammodc. 39. Melttsic. 

e. Amyb'c. 40. Mellitic. 

7. Bensric 41. Morozylic. 

& Boledc. 42. Mucic? 

9. Bombic. 4a Nuiceic? 

IOl Butyric. 44 Nitro-leucic. 

11. Camphoric. 45. Nitro-aaccharic. 

12. Capric, Caproic. 46. Oleic. 
la Carbaaotic 47. Oxalic. 
14. Caceic. 48. Pectic 
]&, Cevadic. 49. Pbocenic. 

16. Choletrteric. 50. Hoic. 

17. CStric. 51. Purpuric 

18. Crocooic 52. Pyrocttric. 

19. Delphinic 5a I^roUtbic. 

20. Ellagic? 54. PyromaUc 

21. Formic. 55. Fyrotartaric 

22. Falmintc. 56. Rosacic. 
2a Fongic 57. .fiackctic. 
24^ GalGc 5a Sebadc 

25. Gbncic 59. Silric 

26. Hinac. 60. Solanic. 

27. Hydrozaiithic 61. Stearic. 

28. lodigoic. 62. Suberic. 
20. Igasaric 6a Suodnic. 
3a Kinic 64. Solpho- 

31. Lacdc naphthalic 

32. Lactic. 65. Sulpbovinic. 
3a Lampic. 66. Tartaric. 

34w litbic or Uric. 67. Vegeto-sulphuric 

The acids of this last dirision are all decom- 
posable at a red heat, and afford generally car- 
bon, hydrogen, oxygen, and in some few cases 
abo nitrogen. The mellitic is found like amber 
in wood coal, and, like it, is undoubtedly of 
organic origin. We shall treat of them all in 
alphabetical order, only joining those adds to- 
gether which graduate, so to q>eak, into each 
other, as hyposulphurousy sulphurous, hypo- 
sttlpbuiic, and sulphuric. 

ACID (ABIETIC). A substance, cry». 
talKsttg in square plates, soluble in alcohol, 
and capable of forming nits with the alkalis, 
extracted from the resin of the Pimu Abies 
by M. Baup of Lausanne. 

ACID (ACERIC). A peculiar acid said 
to exist in the juice of the maple. It is decom- 
poaed by heat, like the other vegetable adds. 

ACID (ACETIC). The same add which, 
in a Tery dilute and somewhat impure state^ 
is called rinegar. 

This add is found combined with potash 
in the juices of a great many plants ; particu- 
lariy the sambucus nigra, phcenix dactilife- 
la, galium verum» and rhus typhinus. Sweat, 



urine^ and even fresh milk, contain it It is 
frequently generated in the stomachs of dys- 
peptfc patients. Almost all dry vegetable 
substances, and some animal, subjected in 
close vesseb to a red heat^ yield it copiously. 
It is the result likewise of a spontaneous fer- 
mentation, to which liquid vegetable, and ani- 
mal matters are liable. Strong acids, as the 
aolpharic and nitric, develop the acetic by 
their action on v^etables. It was long sup- 
posed, on the authority of Boerhaave, that 
the fermentation which {orms vinegar is uni- 
formly preceded by the vinous. This is a 
mistake. Cabbages sour in water, making 
sour crout; starch, in starch-makers* sour 
waters; and dough iiself, wi&out any pre- 
vious production of wine. 

The varieties of acetic adds known in com- 
merce are four: Ist, Wine vinegar; 2d, 
Malt rinegar ; 3d, Sugar rin^ar ; 4^, Wood 
vinegar. We shall describe first the mode of 
making these commerdal 'articles, and then 
that of extracting the absolute acetic add of 
the chemist, either from these vinegars, or 
directly from chemical compounds, of which it 
is a constituent. 

The following is the plan of making vine- 
gar at present practised in Paris. The wine 
destined for vinq;ar is mixed in a large tun 
with a quantity of wine lees, and tiie whole 
bdng transferred into clodi sacks, placed 
within a large iron-bound vat, the liquid 
matter is extruded through the sacks by super- 
incumbent pressure. What passes through 
is put into large casks, set upright, baring 
a small aperture in thdr top. In these it is 
exposed to tlie heat of the sun in summer, or 
to that of a stove in winter. Fermentation 
supervenes in a few days. If the heat should 
then rise too high, it is lowered by cool air, 
and the addition of fresh wine. In the skil- 
ful regulation of the fermentative teroperatura 
consists tiie art of making good wine vinegar. 
In summer, the process is generally completed 
in a fortnight : in winter, double the time is 
requisite. The rinegar is then run off into 
barrels, which contain several chips of birch- 
wood. In about a fortnight it is found to be 
clarified, and is then fit for the market It 
must be kept in close casks. 

The manufacturers at Orleans prefer vrine 
of a year old for making vinegar. But if 
by age the wine has lost its extractive mat- 
ter, it does not readily undergo the acetous 
fermentation. In this case, acetification, as 
the French term the process, may be deter- 
mined, by adding slips of vines, bunches of 
grapes, or green woods. It has been asserted 
that alcohol, added to fermentable Uquor, 
does not increase the product of rinegar. 
But this is a mistake. Stahl observed long 
ago, that if we moisten roses or lilies with 
alcohol, and place them in vessek in which 
they are stirred from time to time, vinegar 
will be formed. He also informs as, if after 



ACID 8 ACETIC. 

« 

abstractiiig the citric acid finom lemon juice sary to buy at -first a small cask of good 

by crabs' eyes (caibonate of lime), we add a vinegar. 

little alcohol to the supernatant liquid, 'and At Gand a Yinegar from beer is made, ih 

place the mixture in a proper temperature, which the following proportions of grain are . 

vinegar will be formed. found to be most advantageous :•— 

Chaptal says, that two pounds of weak 1880 Paris lbs. malted barley, 

spirits, sp. gr. 0.985, mixed with 300 grains 700 t- wheat 

of beer yeast and a little starch wate^ pro- 500 — buckwheat 

duced extrsmely strong vinegar. The Ikad These grains are ground, mixed, and boiled; 

was developed on the fifth day. Tlie eame along with twenty-seven casks-full of river 

quantity of starch and yeast, without the water, for three hours. Eighteen casks of 

spirit, fermented more slowly, and yielded a good beer for vinegar are obtained. By a 

weaker vin^ar. A slight motion is found subsequent decoction, more fermentable liquid 

to favour the formation of vinegar, and to is extracted, which is mixed with the former, 

endanger its decomposition after it is made. The whole brewing yields 3000 English 

Chap^ ascribes to agitation the operation of quarts. 

thunder ; though it is well known, that when In this country, vinegar is usually made 

the atmosphere is highly electrified, beer is from malt By mashing with hot water, 

apt to become suddenly sour, without the 100 gallons of wort are extracted in less than 

concussion of a thunder-storm. In cellars two hours fiiom 1 boll of malt When the 

exposed to the vibrations occasioned by the liquor has fallen to the temperature of 75^ 

rattling of carriages, vinegar does not keep Fahr. 4 gallons of the bann of beer are 

welL The lees, which had been deposited by added. After thirty-six hours it is racked 

means of isinglass and repose, are thus jum- ofi'into casks, which are laid on their sides, 

bled into the liquor, and make the fermenta- and exposed, with their bungrholes loosely 

tion recommence. covered, to the influence of the sun in sum- 

Almost all the vinegar of the north of mer ; but in winter they are arranged in a 

Francs being prepared at Orleans, the manur stove-room. In three months this vinegar ia 

facture of ^at place has acquired such celer ready for the manufiicture of sugar of lead, 

brity, as to render their process worthy of a To make vinegar for domestic use, however, 

separate consideration. the process is somewhat different Hie above 

The Orleans casks contain nearly 400 Hquor is racked off into casks placed upright, 

pints of wine. Those which have been al- having a false cover pierced with holes fixed 

ready used are preferred. They are placed at about a foot from their bottom. On this 

in three rows, one over another, and in the a considerable quantity of rape, or the refuse 

top have an aperture of two inches diameter, from the makers of British wine, or otherwise 

kept always open. The wine for acetification a quantity of low priced raisins, is laid. The 

is kept in adjoining casks, containing beech liquor is turned into another barrel every 

shavings, to which the lees adhere. The twenty;four hours, in which time it has begun 

wine thus clarified is drawn off to make vine- to grow warm. Sometimes, indeed, the vine- 

gar. One hundred pints of good vinegar, gar is fully fermented, as above, without the 

boiling hot, are first poured into each cask, rape, which is added towards the end, to com- 

and Idt there for eight days. Ten pinto of municate flavour. Two laige casks are in 

wine are mixed in, every «ght days, till the this case worked together, as is described long 

vessels are full. The vinegar is allowed to ago by Boerhaave, as follows :— 

remain in this state fifteen days, before it is •< Take two large wooden vats, or hogsheads, 

exposed to sale. and in each of these place a wooden grate or 

The uted casks, called moihen, are never hurdle^ at the distance of a foot from the hoi- 

emptied more than half, but are successively tom. Set the vessel upright, and on the grate 

filled again, to acetify new portions of wine, place a moderately close layer of green twigs. 

In order to judge if the mother works, the or fresh cuttings of the vine. Then fill up 

vinegar-makers plunge a spatula into the li- the vessel with the footstalks €i grapes, conw 

quid ; and according to the quantity of froth monly called the rape, to the top of the vessel, 

which the spatula shows, they add more or which must be left quite open, 

less wine. In summer, the atmospheric heat " Having thus prepared the two vessels, 

is sufficient In winter, stoves heated to about pour into them the wine to be converted into 

76^ Fahr. maintain the requisite temperature vinegar, so as to fill one of them quite up, 

in the manufactory. and the other but half full. Leave them 

In some country districts, the people keep tlius for twenty-four hours, and then fill up 

in a place where the temperature is mild and the half filled vessel with liquor from that 

equable, a vinegar cask, into which they pour which is quite full, and which will now in its 

such wine as they wish to acetify ; and it is turn only be left half full Four-and-twenty 

always preserved full, by replacing the vine- hours afWwards repeat the same operation, 

gar drawn off by new wine. To establish and thus go on, keeping the vessels alternately 

this household manufacture, it is only neces- full and half full during twenty-four hours. 



ACID 



9 



ACETIC. 



tiU the TUB^gar be made. On the second or 
third day there will arise in the half filled 
venel a fermentatiTe motion, accompanied 
m'tfa a senaible heat, which will gradually in- 
crease from day to day. On the contrary, 
the fermenting motion is almost imperceptible 
in the full vessel ; and as the two vessels are 
alteniately full and half fiill, the fermentation 
is by this means in some measure interrupted, 
and ia only renewed every other day in each 
veiseL 

** Wl^n this motion appears to have entirely 
ceased, even in the half filled vessel, it is a sign 
that the fermentation is finished ; and therefore 
the vinegar is then to be put into casks close 
stopped, and kept in a cool place. 

''.A greater or less degree of warmth ac- 
celerates or checks this, as well as the spiritu- 
ixis fevmentadon. In France it is. finished 
in about fifteen days, during the summer; 
but if the heat of the air be very great, and 
exceed the twenty-fifth degree of Reaumur's 
thermometer (88^^ Fahr.), the half filled 
yessel must be filled up every twelve hours ; 
because, if the fermentation be not so checked 
in that time, it will become violent, and the 
liquor will be so heated, that many of the 
spirituous parts, on wbidi the strength of the 
vinegar depends, will be -dissipated, so that 
nothing will remain after the fermentation but 
A vapid liquor, sour indeed, but effete. The 
better to prevent the dissipation of the spi- 
rituous parts, it is a proper and usual pre- 
caution to dose the moutii of the half filled 
vessel, in which the liquor ferments, with a 
cover made of oak wood. As to the full 
Teasel, it is always left open, that the air may 
act freely on the liquor it contains ; for it is 
not liable to the same inconveniences, becHuse 
it ferments very slowly." 

Good rinegar may be made from a weak 
syrup, consisting of 18 oz. of sugar to every 
gallon of water. The yeast and rape are to 
be here uaed as above described. "Whenever 
the vinegar (from the taste and flavour) is 
considered to be complete, it ought to be 
decanted into tight barrels or bottles, and 
well secured from access of air. A momen- 
tary ebulhdon before it b bottled is found 
fappurable to its preservation. In a large 
mamifactory of malt vinegar, a considerable 
revenue ia derived firom the sale of yeast to 
the bakers. 

Vinegar obtained by the preceding methods 
Jias more or less of a brown colour, and a 
peculiar but rather grateful smell. By distiU 
Jatioti in glass vessels, the colouring matter, 
which resides in a mucilage, is separated, but 
die fragrant odour is generally replaced by 
ao empyreumatic one. The best French wine 
iniiegars, and also some from malt, contain a 
little alcohol, which comes over early with 
the vratery part, and renders the first product 
of distillation scarcely denser, sometimes even 
leas dense, than water. It is accordingly 



rejected. Towards the end of tb« distillatiott 
the empyreuma increases. Hence only the 
intermediate portions are retained as distilled 
vinegar. Its specific gravi^ varies from 1.005 
to 1.015, while that of common vinegar of 
equal strength varies from 1. 010 to 1.025. 

A crude vin^ar has been long prepared 
for the calico printers, by siibjecting wood 
in ir6n retorts to a strong red heat. The 
following arrangement of apparatus has been 
found to answer well. A series of cast-iron 
cylinders, about 4 feet diameter, and 6 feet 
long, are built horizontally in brick-work, so 
that the flame of one furnace may play round 
about two cylinders. Both ends prcject a 
little from the brick-work. One of them 
has a disc of cast-iron well fitted and firmly 
bolted to it, fVom the centre of which disc an 
iron tube, about 6 inches diameter, proceeds^ 
and enters at a right angle the main tube of 
refrigeration. Hie diameter of this tube 
may be from to 14 inches, according to the 
number of cylinders. The other end of the 
cylinder is called the mouth of the retort. 
This is closed by a disc of iron, smeared 
round its edge with clay-lute, and secured 
in its place by wedges. Hie charge of wood 
for such a cylinder is about 8 cwt. The 
hard woods, oak, ash, birch, and beech, are 
alone used. Fir does not answer. The heat 
is kept up during the day-time, and the fur- 
nace b allowed to cool during the night. 
Next morning the door is opened, the char- 
coal removed, and a new charge of wood is 
intioduced. Hie average product of crude 
vinegar called pyrolignous acid is 35 gallons. 
It is much contaminated with tar; is of a 
deep brown colour; and has a sp. gr. of 
1.025. Its total weight is therefore about 
300 lbs. But the residuary charcoal is found 
to weigh no more than one-fifUi of the wood 
employed. Hence nearly one-half of the 
ponderable matter of the wood b dissipated 
in incondensable gases. Count Rumford 
states, that the charcoal b equal in weight to 
more than four-tenths of the wood from 
which it is made. The Count's error seems 
to have arisen from the slight heat of an oven 
to which hb wood was exposed in a glass 
cylinder. The result now given b the expe- 
rience of an eminent manufacturing chemist 
at Glasgow. The crude pyrolignous acid b 
rectified by a second distillation in a copper 
still, in the body of which about 20 gallons 
of viscid tarry matter are left from every 100. 
It has now become a transparent brown vil 
negar, having a considerable empyreumatic 
smell, and a sp. gr. of 1.013. Its acid powers 
are superior to those of the best household 
vinegar, in the proportion of 3 to 2. By 
redistillation, saturation with quicklime, eva- 
poration of the liquid acetate to dryness, and 
gentle torrefaction, the empyreumatic matter 
is so completely dissipated, that on decom- 
posing the calcareous salt by sulphuric acid. 



ACID 10 ACETIC 

a pure, perfectly colourieM, and grateAil vine- drometer of Fahrenheit's construction is used 

gar rises in distillation. Its strength will be for finding the specific gravities. It consists 

proportional to the concentration of the de- of a globe about 3 inches diameter, having a 

composing add. l'^® ballast baU drawn out beneathi and a 

The acetic acid of the chemist may be stem above of about 3 inches long, contain- 
prelMied in the following modes : — 1st, Two ing a slip of paper with a transverse line in 
parts of fused acetate of potash, with one of the middle, and surmounted with a little cup 
the strongest «1 of vitriol, yield, by slow dis- for receiving weights or poises. The experi- 
tillation from a glass retort into a refriger- ments on which this insbnment, called an 
ated receiver, concentrated acetic acid. A Acetometer, is constructed, have been detailed 
small portion of sulphuxous acid, which con- in the sixth volume of the Journal of Science, 
taminates it, may be removed by redistiila^ They do not diflTer essentially from those of 
tion from a little acetate of lead. 2d, Or Mollerat. The following points were deter- 
4 parts of good sugar of lead, with I part of mined by this chemist. The add of sp. gr. 
sulphuric add treated in the same way, afford 1.063 requires 2^ times its wdght of crys- 
a sliirhtly weaker acetic add. 3d, Gently tallised subcarbonate of soda for saturation^ 
caldned sulphate of iron, or green vitriol, whence M. Thenard regards it as a com- 
mixed with sugar of lead in the proportion pound of 11 of water, and 89 of real acid in 
of 1 of the former to 2^ of the latter, and the 100 parts. Combined with water in the 
carefully distilled from a porcelain retort into proportion of 100 to 112.2, it does not 
a cooled recdver, may be also considered a change its density, but it then remains liqpiid 
good economical process. Or without dia- several degrees below the freezing point of 
tillation, if 100 parts of well dried acetate of water. By diluting it with a smaller quan- 
lime be cautiously added to 60 parts of strong tity of water, its sp. gr. augments, a drcum- 
sulphuric acid, diluted with 5 parts of water, stance peculiar to Uus add. It is 1.079, or 
and digested for 24 hours, and strained, a at its mtmmumt when the water forms one- 
good acetic add, suffidently strong for every third of the weight of the add. — Ann. de 
ordinary purpose, will be obtained. Chimie, torn. 66. 

The distillation of acetate of copper or of The following table is given by Messra 

lead per se, has also been employed for ob- Taylor, as tlie basis of thdr acetometer: — 

taining strong add. Here, however, the Revenue proof add, called by the manii- 

product is mixed with a portion of the fra- facturer No. 24. 

giant pyro-acetic spirit, which it is trouble- sp. gr. 1.0085 contains real add in 100, 5 

some to get rid of. Undoubtedly the best 1.0170 - - - - 10 

process for the strong acid is that first de- 1.0257 - - - - 15 

scribed, and the cheapest the second or third. 1.0320 - - - . 20 

When of the utmost possible strength ita 1.0470 . - - - 30 

sp. gravity is 1.062. At the temperature of 1.0580 - ... 40 

50^ F. it assumes the solid form, crystalliz- An acetic add of very considersble strength 

ing in oblong rhomboidal plates. It has an may also be prepared by saturating perfectly 

extremely pungent odour, affecting the noa- dry charcoal with common vinegar, and then 

trils and eyes even painfully, when its vapour distilling. The water easily comes off, and 

is incautiously snuffed up. Its taste b emi- is separated at first; but a stronger heat is 

nently add and acrid. It excoriates and in- required to expel the add. Or by exposing 

£ames the skin. vinegar to very cold air, or to freezing raix- 

Tbe purified wood vinegar, which is used tures, its water separates in the state of ioe, 

for pickles and culinary purposes, has com- the interstices of which are occupied by a 

monly a specific giaviiy of about 1.009; strong acetic acid, which may be procured by 

when it is equivalent in add strength to good dndning. The acetic add, or radical vinegar 

wine or malt vinegar of 1.014. It contains of the apothecaries, in which they dissolve • 

about WU of ite wdght of absolute acetic little camphor or fragrant essential oil, baa 

■ » J iQ i. . A • ^ j..#« «r aspedficgravityof about 1.070. It containa 

.ad, and i§ of water. An exc.se duty of P^ ^^^ i^er to 2 of the c.r>t>IIi*ed 

♦d. tt levied on e»ery gaUon of ""eg" of ^ ^ ^ ^^ J^^^^ ^^ 

the above sti^gth. ThB. however. » a»^ ^ ^ moiuened with that acid, 

estomated duectly by .to .^ gr. but by l^ ^ ^^f^^ ^ ^ . ^ 

\. of the calceo™ acetate is n«r.y douMe rJ^-^^S^-Jr:!"'.^™™"^:.::; 

that of the pure wood vinc^. Thu« 1.009 . . , "^ 

in vinegar, become. 1.018 in l^uid «»tate. ' .^ „ jj .^rti in the acetMe. of 

But the v.neg» of fermentation =1.014 wJl ,„d of lead, h«. been an.ly»d by 

^^^^"^^ If^J^ T ^ J^^J MM. Gay Ia»«c a^d n»n«d, »J^ bj 

0.005 be subtracted for muali^ or ex- ^^ .. ' ' ' 

tractive, the remainder will agree with the den- /-. » * *• i tax qom u^^ k «oo 

* lu a a. r •''^ A^^i.^ I.- Gay Lussac found 50.224 carbon, o.o2v 

Mty of the acetate from wood. A glass ny- ^ 



ACID 



11 



ACETIC. 



hydragai* and ikl47 oxygen ; or, in other 
tanni» ^224 carbon, 4<(.91 1 of water, or ita 
cJeoMnCary constituenta» and 2.863 oxygen 
in exceM. 

BerzeUus,— 46.83 caib. 6.33 bydrog. and 
4&88 oxygen, in tbe hundred parts. 

Dr Aoot, in bie excellent paper on Ali- 
mentary Substances, (Phil, Tranaaci. 1827, 
Psft ii.)v finds that the hydrogen and oxygen 
of acetic add exist in it, in the proportions 
In which tbeyfonn water;— his proportions 
of the constituents agreeing with the results 
of Berselius, or carbon 47.0&, water 52.95, 
in 100 parts. 

Hieir methods are described under Veob- 
TABLB (Analysis). By saturating known 
weights of bases with acetic add, and ascer- 
taining the quantity of acetates obtained afUr 
esotioiiB eraporation to dryness, Berselius 
obtained with lime (3.56) 6.5 for the prime 
equiTalent of acetic add, and with yellow 
oxide of lead 6.432. 

Acetic add dissolves resins, gum resins, 
camphor, and essential oils. Its odour is em- 
phrfed in medicine to relieve nervous head- 
adie, Ihinting fits, or sickness occasioned by 
laowded* rooms. In a slightly dilute state, 
itt applicatioii has been found to check he- 
moniiagy from the nostrils. Its andconta- 
^us powers are now little trusted ta It 
is Terv largely need in calico-printing. Mo- 
derately rectified pyrolignous add has been 
raoommended for the preservation of animal 
Ibod; but the empyreumatic taint it com- 
municates to boffies immersed in it, is not 
qmle removed by thdr subsequent ebullition 
in water. See Acm (Pybouonoos). 

Acetic add and common vinegar are soroe- 
times fraudulently mixed with sulphuric add 
to give them strength. Tliis adulteration may 
be detected by the addition of a little chalk, 
short of their saturation. With pure vinegar 
the calcareous base forms a limpid solution, 
but with sulphuric add a white insoluble 
gypsnm. Muriate of baryta is a still nicer 
test. British fermented vinegars are allowed 
by law to contain a little sulphuric acid, but 
tfie quantity is frequently exceeded. Copper 
is duoovered in vinegars by supermturating 
them with aonmonia, when a fine blue colour 
is produced ; and lead by sulphate of soda, 
hy&oaolpiiuretB, and sulphuretted hydrogen. 
None of these should produce any change on 
genuine vinegar. See Lead. 

Acetic add dissolves deutoxide of barium 
widiout effervescence. By predpitating the 
barjta with sulphuric add, there remains an 
oxyg«nixed acid, which, being saturated with 
pottsb, and heated, allows a great quantity of 
oxygen gas to escape. Thm is disengaged 
aft tha same time a notaUe quantity of carbo- 
nic add gas. This shows that the oxygen, 
when assiriffd by hcat^ unites in part witfi the 
carbon, and doubtka likewise with the hy- 



drogen, of the add. It is in Act acetic deut- 
oxide of hydrogen. 

Salts consisting of the scvend bases, united 
in definite proportions to acetic add, are called 
acetates. Tbey are characterized by the pun* 
gent smell of vinegar, which they exhale on 
the affusion of sulphuric add ; and by their 
yielding on distillation in a moderate red heat 
a very light, odorous, and combustible liquid 
called pyro-acetic (sfiut) ; which see. Hiey 
are all soluble in water; many of them so 
much so as to be uncrystallizable. About 
30 different acetates have been formed, of 
which only a very few have been applied to 
the uses of life. 

The acetic add unites with all the alkalis 
and most of the earths, and with these bases 
it forms compounds, some of which are crys* 
tallixable. The salts it forms are distinguish- 
ed by their great solubility ; thdr decompo- 
mtion by fire, which carbonizes them; the 
spontaneous alteration of thdr solution ; and 
thdr decomposition by a great number of 
adds, which extricate from them tbe acetic 
add in a oonoentraAed state. It unites like- 
wise with most of the metallic oxides. 

With baryta, the saline mass, by spon- 
taneous evaporation, crystallizes in fine trans- 
parent prismatic needles, of a bitterish add 
taste, which do not deliquesce when exposed 
to the air, but rather effloresce. 

With potash tliis add unites, and forms a 
deliquescent salt scarcely crystallizable, called 
formerly foliated earth, of tartar, and regene- 
rated tartar. The solution of this salt, even 
in closely stopped vessels, is spontaneously de- 
composed. 

With soda it forms a crystallizable salt, 
which does not deliquesce. 

Tlie salt formed by dissolving chalk or 
other calcareous earth in distilled vinegar, has 
a sharp bitter taste, and appears in the form 
of silky crystals. 

llie acetate of strontia has a sweet taste^ 
is very soluble, and is easily decomposed by a 
strong beat. 

The salt formed by uniting vinegar with 
ammonia, andently called Spirit of Minde- 
rerus, is generally in a liquid state, and is 
commonly believed not to be crystallizable. 
It nevertheless may be reduced into the form 
of small needle-shaped crystals, when this 
liquor is evaporated to the consistence of a 
syrup. 

With magnesia the acetic add fisrms a 
visdd saline mass, which does not shoot into 
crystals, but remains deliquescent, has a taste 
sweetish at first, and afterwards bitter, and is 
soluble in spirit of wine. 

Gludne is readily dissolved by acetic add. 
This solution, as Vauquelin informs us, does 
not crystallize ; but is reduced by evaporation 
to a gummy substance, which slowly becomes 
dry and brittle ; retaining a kind of ductility 



ACID 12 ARSENIC. 

for m long time. It has a Mocharine and cribed by M. Ttinnennann in TrommfldorflTa 
pretty strongly astringent taste, in which that JournaL Equal parts of starch and black 
of TiAegar however is distinguishable. oxide of manganese are to be well mixed, and 
Yttria dissolves readily in acetic acid» and put into a retort so as to fill one-fourth of it, 
the solution yields by evaporation crystals of and then a third equal part of water added, 
acetate of jrttria. These have commonly the and made to moisten the mass equably. A 
form of thick six-sided plates, and are not receiver being adapted, heat is applied, and 
altered by exposure to the air. three parts of muriatic acid are gradually add- 
Acetate of alumina is commonly made by ed through a feeding tube. Ilie product is 
adding gradually to a boiling solution of alum impure amylic add, which is saturated with 
in water a solution of acetate of lead, till no caibonate of lime, and evaporated so as to 
further precipitate ensues. The sulphate of yield crystals of amylate of that base. Tbese^ 
lead having subsided, decant the supernatant purified by further crystallization, are de- 
liquor, evaporate^ and the acetate of alumina composed by 73 per cent of sulphuric add, 
may be obtained in small needle-shaped crys- whence, by distillation, pure amylic add is 
tals, having a strong styptic and acetous taste, obtained. It is sour, reddens vegetable blues. 
This salt is of great use in dydng and calico- readily evaporates with a sharp odour resem- 
printing. See Alumina. bling hydrocyanic acid. Its salts are mostlj 
Acetate of sirconia may be formed by pour- soluble, and even deliquescent. They reduce 
ing acetic acid on newly precipitated sirconia. nitrate of silver and muriate of gold. The 
It has an astringent taste. It does not crys- amylate of lime. occurs in octangular crystals 
talUze; but when evaporated to dryness, forms mingled with plates. It consists of 42.16 
a powder, which does not attract moisture lime, and 57.84 amylic add. Amylate of 
from the air. It is very soluble both in water barytes forms quadrilateral prisms, and con- 
and alcohol ; and is not so easily decomposed sists of 57.29 baryta, and 29.24 amylic add, 
by heat as nitrate of sirconia. with 13.47 water. The salts of potMh, soda. 
Concerning the action of vinegar on alcohol, and ammonia, are deliquescent. The ultU 
see £TH£a. mate constituents of amylic add are said to 

M. Vauquelin has found that acetic acid be 2.5 carbon, and 3 oxygen, 

may be combined with volatUe oils. See ACIDS (ANTIMONIC AND ANTL 

Oils (Volatile). MONIOUS). See Antimony. 

See Sfibit (Pybo-acetic). ACID (ARSENIC). We ar« indebted to 

Vinegar dissolves the true gums, and partly Scheele for the discovery of this acid, though 

the gum resins, by means of digestion. Maoquer had before noticed its combinationa. 

See Salt, for a tabular view of the con- It may be obtained by various methods. If 

atitution of the Acetates. six parts of nitric acid be poured on one of 

ACID (ALGETIC). Tlie name, hardly the concrete arsenious add, or white arsenic 

appropriate, given by M. Licbeg to the bitter of the shops, in the pneumato-chemical ap- 

of aloes ; a substance supposed by him to be a paiatus, and heat be applied, nitrous gas vrill 

compound of carbasotic acid and a peculiar be evolved, and a white concrete substance, 

resinous-Uke matter. The bitter of aloes may differing in its properties from the arsenious 

be formed in large quantity, by acting upon acid, will remain in the retort This is the 

aloes with nitric add of the sp. grav. 1.25. arsenic add. It may equally be procured by 

The substance obtained forms a purple salt means of aqueous chlorine, or by heating 

with potash, but little soluble, and predpitates concentrated nitric add with twice its weight 

the salts of baryta, lead, and peroxide of iron, of the solution of the arsenious add in muri- 

of a deep purple colour. Ann, de Chim. atic add. The concrete acid should be ez- 

zxxvii. 171. posed to a dull red heat for a few minutes. 

ACID (AMNIOTIC). On evaporating In either case an add is obtained that does 

the liquor amnii of the cow to one-fourth, not crystallize, but attracts the moisture of the 

Vauquelin and Buniva found that crystals air, has a sharp caustic taste, reddens blue 

form in it by cooling. These crystals, when vegetable colours, is fixed in the fire, and of 

washed with a little water, are white and the spedfic gravity of 3.391. 

shining, slightly add to the taste^ redden lit- If the arsenic acid be exposed to a red beat 

mus paper, and are a little more soluble in hot in a glass retort, it melts and becomes trans- 

than cold water. With the alkalis this acid parent, but assumes a milky hue on cooling. 

forms very soluble salts, but it does not d». If the heat be increased, so that the retort 

compose the carbonate without the assistance begins to melt, the add boils, and sublimes 

of heat. into the neck of the retort. If a covered 

Dr Prout could not find this add in the crucible be used instead of a glass retort, and 

amniotic liquor of the cow, though he sought a violent heat applied, the add boils strongly, 

for it with much pains. Hence its existence and in a quarter of an hour b^ins to emit 

is questionable. fumes. These, on being recdved in a glass 

ACID (AMYLIC). This new add com- bell, are found to be arsenious add; and a 

pound of carbon and oxygen has been des- small quantity of a transparent glass, diflicult 



ACID 43 ARSENIC. 

to hat, will be found lining the sidei of the apple-green precipitate. Tliese precipitates 

cmdbiew This is aneniate of alumina. redissolve, on adding a small quantity of the 

Combustible substances decompose this acid which previously held them in solution. 

add, and eliminate metallic arsenic. Orfila says, that arsenic add gives, with 

With phosphorus, phosphoric acid is ob- acetate of copper, a bluiab^white precipitate, 

tained, and a phosphuret of arsenic, which but that it exercises no action ei^er on the 

sublimes. muriate or acetate of cobalt; but with the 

According to Lagrange, two parts of water ammoni&.muriate it gives a rose-coloured pre- 

are sufficient to diasolve one of arsenic acid, cipitate. Arsenic acid ought to be accounted 

It cannot be crystallixed by any means ; but a more violent poison than even the arsenious. 

oo evaporation assumes a thick honey-like According to Mr Brodie, it is absorbed, and 



occasions death by acting on the brain and the 

Arsenic add combines with the earthy and heart 

alkaline bases, and forms salts very different A solution of pure arsenic add mixed with 

Irom those furnished by the arsenious add. common sugar powdered, beccnnes in some 

All these arseniates are decomposable by houra of a reddish colour, then of a magnifi- 

charooal, which separates arsenic from them cent purple : ndthor arsenious add, the arse- 

by means of heat. nites, nor phosphoric add, produce any simi- 

Benelius, from the result of accurate ex- lar effect 

perimentB on the arseniates of lead and baryta. Arsenic acid saturated with potash does not 

infers the prime equivalent of arsenic add to crystallise. 

be 14.4569, oxygen bdng 1.0. The bi-arseniate of potash is fabricated 
On this supposition, Benelius*s insoluble on the great scale in Saxony, by fusing toge- 
sslts will consist of two primes of base and one ther equal parts of nitre and arsenious add ; 
of add ; and the add itself will be a com- dissolving the mdted mass, and crystallising 
pound of 5 of oxygen = 5 -^ 9.5 of the me- the salt The crystals are large. By the 
tallic baae^ 14fb5; for direct experiments analysisofM. Berzelius, they consist of anenic 
have rfiown it to consist of 100 metal, and acid 63.87, potash 86.16, water 9.97. — Jnn. 
about 53 oxygen. But 153 : 100 : : 14.5 : de Chim, et de Phyu xix. 366. 
9.5 nearly. By Dr Thomson their composition is» arse- 
While Piroust and Benelius concur in as- nic add 68.5, potash 26.5, water 5. Mit- 
signing the proportion of 53 oxygen to 100 scherUch*s statement is in accordance with 
nwtal in this add, Thenard states ito com- Berzelius's equivalent number, 
position at 56.25 to 100, and Dr Thomson With lime water this add forms a predpi- 
at 61.4 to 100. By the latter authority, ita tate of arseniate of lime, soluble in an excess 
prime equivalent becomes 4.75 metal -^3 of ita add, though insoluble alone. 
ofxygen =s 7.75 ; and that of arsenious add If arsenic acid be saturated with magnesia, 
4.75 -|- 2 =: 6.75. a thick substance b formed near the point of 

All ita salts, with the exception of those of saturation, 

potash, soda, and ammonia, are insoluble in Arseniate of baryta is insoluble, and un- 

water; but except arseniate of bismuth, and crystallizable, but soluble in an excess of the 

one or two more, very soluble in an excess acid. 

^ of arsenic acid. Hence, after baryta or It consists, by Berzelius, of 57 baryta -^ 

oxide of lead has been predpitated by this 43 arsenic add. The bi<«rBeniate of baryta 

add, ita farther addition redissolves the pre- crystallises. It is made by dissolring the 

* dpitate. This b a useful criterion of the neutral salt in arsenic add. It contains 

add, joined to ita reduction to the metallic twice the quantity of add which exista in the 

state by charcoal, and the other characten former. 

already detailed. Sulphuric acid decomposes With soda in suffident qi|antity to saturate 

the arseniates at a low temperature^ but the it, arsenic add forms a salt crystallizable like 

sulphates are decomposed by arsenic add at a die acidulous arseniate of potash. To form the 

red beat, owing to the greater fixity of the neutral aneniate, carbonate 6f soda should be 

latter. Phosphoric, nitric, muriatic, and added to the add, till the mixture be d»- 

ihioric adds, dissolve, and probably convert ddedly alkaline. This salt crystallizes from 

into subsalta all the arseniates. I'he whole the concentrated solution. It is much more 

of them, as well as arsenic add itself when soluble in hot than in cold water. Pelletier 

decomposed at a red heat by charcoal, yield says, that the crystab are hexaedral prisms 

the diaracteristic garlic smell of the metallic terminated by planes perpendicular to thdr 

vapour. Nitrate of silver gives a pulverulent axis. 

bricL-odoured predpttate, with arsenic add. 100 parte of arseniate of soda aie composed^ 

The add itself does not disturb the transpa- by the experimento of Berzelius, of arseiuc 

rency of a solution of sulphate of copper; add 29.29, soda 15.88, water 54.84. The 

but a neutral arseniate gives with it a bluish- triple salt, called arseniate of potash and sod% 

green predpitate ; with sulphate of cobalt a easily crystallises. It consists, according to 
dirty red; and vrith sulphate of nickelj an 



ACID 



14 



ARSENIOUS. 



the mna cfaemist, of aneniate of potad^ 9(XS4 

Arseniate of soda, 26.65 
Water, 44.11 

The hi-araeniate of soda is obtained by add- 
ing arsenic acid to the solution of the neutral 
salt, till the mixture no longer gives a preci- 
pitate with muriate of baryta. It is very 
soluble in water. It consists of 
Arsenic acidt 63.16 
Soda, 17.13 

Water, 19.71 

Combined with amnaonia, arscsicacid foims 
a salt affording rbomboidal crystals analogous 
to those of the nitrate of sodit 

To form this salt, we must add ammonia to 
the concentrated solution of the acid, till a 
precipitate fidL On heating the solution, 
the precipitate is dissolved. If we set the 
liquid aside, taking care that too much of the 
ammonia d<»es n«>t exhale, there is formed, 
after some time, large and beautiful crystals 
of the neutnU salt Hie crystals which some- 
times fbll during the cooling of this solution 
are a sub>arseniate. The neutral arseniate of 
ammonia decomposes in the air. It consists 
ofafBenic acid, 65.28 
Ammonia, 19.44 
Water, 15.28— Af it jcA^/icA. 
Bi-arseniate of ammonia is formed by adding 
arsenic acid to ammonia till litmus paper be 
strongly reddened by the solution, and till it 
no longer precipitates muriate of baryta. We 
then obtain by evaporation crystals which do 
not change on exposure to the air. It consists, 
according to Benelius, of arsenic acid 72.30, 
ammonia ia77, water 16.93» in 100 parts. 
The arseniate of soda and ammonia is formed 
by mixing the two separate arwniates ; and 
the compound salt gives crystals with brilliant 
faces. If we redissolve the crystals, and then 
lecrystallice, we should add a little ammonia, 
otherwise the salt will be acidulous from the 
escape of some ammonia. 

Arsenic acid does not act on gold or plati- 
, na; neither does it on mercury or silver with- 
out the aid of a strong heat ; but it oxidizes 
copper, iron, lead, tin, sine, bismuth, antimony, 
cobalt, nickel, manganese, and arsenic. 

Aneniate of cobalt has been discovered 
at the lead mine of Tyncsbottom, near Alston 
in Cumberland, in the form of a rose-colour- 
ed eiBorescence investing hepatic and com- 
mon pyrites. The veins are worked in a 
limestone stratum. 

This acid is not used in the arts, at least 
directly, though indirectly it forms a part of 
some compositions used in dyeing. See Salts 
(Tablb of). 

ACID (ARSENIOUS). Fourcroy was 
the first who distinguished by thb name the 
white arsenic of tlie shops, which Scheele had 
proved to be a compound of the metal arsenic 
with oxygen. 

lliis acid, which is one of the most virulent 
poiftons known, frequently occurs in a native 



stat% if not very abundantly ; and it is ob* 
tained in roasting several ores, particularly 
those of cobalt. In the chimn^s of the fur- 
naces where this operation is conducted, it 
generally condenses in thick semitransparent 
masses ; though sometimes it assumes the form 
of a powder, or of little needles, in which state 
it was formerly called flowers of arsenic. 

The arsenious add reddens the most sei^ 
flible blue v^etaUe colours, though it tnrna 
the syrup of violets green. On exposure to 
the air it becomes opaque, and covered with 
a slight efllorescence. Throvm on incan- 
descent coals, it evaporates in white fumes* 
with a strong smell of garlic. In close vesaela 
it is vobrtilized ; and, if the heat be strong, 
vitrified. The result of this vitrification is a 
transparent glass, capable of crystallizing in 
tetrsi^ra, the angles of which are truncated. 
Jt is easily altered by hydrogen and carixm, 
which deprive it of its oxygen at a red heat, 
and reduce the metal, the one fonning water, 
the other carbonic acid, vrith the oxygen taken 
from it; as it is by phosphorus, and by 
sulphur, which are in part converted into 
adds by its oxygen, and in part form an 
arsenical phosphuret or aulphuret with the 
arsenic reduced to the metallic state. Its sp^ 
dfic gravity is 3.7. 

It is soluble in thirteen times its vreight of 
boiling water, but requires eighty times its 
wdght of cold. Hie solution crystallizes, and 
the acid assumes the form of regular tetrae- 
drons, according to Fourcroy ; but according 
to Lagrange, of octaedrons, and these fre- 
quently varying in figure by different laws 
of decrement. It crystallizes much better by 
slow evaporation than by simple cooling. 

The solution is very acrid, reddens blue 
colours, unites vrith' the earthy bases, and de- 
composes the alkaline sulphurets. Arsenioua 
add is also soluble in oils, spirits, and alco- 
hol ; the last taking up from 1 to 2 per cent. 
It is composed by Berzeliusof 9.5 of metal-f- 
3 oxygen ; and its prime equivalent b therefine 
12.5. But Dr Thomson considers it asa com- 
pound of 4<.75 metal -|- 2 oxygen = 6b 75. 

Dr WoUaston first observed, that when a 
mixture of it with quicklime is heated in a 
glass tube^ at a certain temperature^ ignition 
suddenly pervades the mass, and metallic 
arsenic sublimes. As arseniate of lime is 
found at the bottom of the tube^ we perceive 
that a portion of the arsenious add is robbed 
of its oxygen, to complete the addification of 
tlie rest. 

Tlie action of the other acids upon the arse- 
nious is very different from that which they 
exert on the metal arsenic. By boiling, sul- 
phuric add dissolves a small portion of it, 
which is predpitated as the solution cools. 
Nitric add does not dissolve it, but by the 
help of heat converts it into arsenic add. 
Aqueous chlorine acidifies it completely, so 
as to convert it into arsenic acid. 



ACID 



15 



ARSENIOUa 



AfKBious add combines with the emthy 
and alkaline bases* The earthy mnenites pos- 
eeas little solubility; and hence the solutions 
of baryta, strontia, and lime, form predpi* 
tatea with that of arsenious add« 

With the fixed alkalis the arsenious acid 
forms viscid awcnites, which do not crystal- 
liae^ and which are decomposable by fire, 
the arsenious add bdng Tolatilised by the 



With anunonia it forms a salt oqpable of 
crystalllaation. 

"Die nitrates act on the arsenious add in a 
veiy remarkable manner. On treating the 
nitrstes and arsenious add together, nitrous 
vapour is extricated : part of its oxygen is 
a beotbed by the arsenious add; it is thus 
converted into arKuic add, and an arseniate 
is left in the retort. Hie same phenomena 
take place on detonating nitrates with arse- 
nious add; for it is still suffidently com- 
bustible to produce a detonation, and a true 
arseniate remains at the bottom of the crud- 
blew It was in this way chemists jformerly 
prepared thdr fixed arsenic, which was the ad- 
dnlous arseniate of potash. The nitrate of 
ammnnia exhibits different phenomena in its 
decomposition by arsenious add, and requires 
rooa<ierBble precaution. Pelletier, having 
mixed equal quantities, introduced the mix- 
tore into a large retort of coated glass, placed 
in a r eve i be r atwy furnace, with a globular 
recdver. He b^an with a very slight fire ; 
for the decomposition is so rapid, and the ni- 
trous vapours issue with such force, that a 
portion of the arsenious add is carried off 
undeoomposed, unless you proceed very gen- 
tly. Chlorate of potash, too, by completely 
oxidiang the arsenious acid, converts it into 
arsenic add, which, by the assistance of heat, 
is capable of decomposing the muriate of pot- 
ash that remains. 

Axaenioos add b used in numerous in- 
stances in the arts, under the name of white 
arsenic, or of aneoic simply. In many cases 
it is reduced, and acts in its metallic state. 

Many attempts have been made to intro- 
duce it into medidne ; but as it is known to 
be one of the most violent poisons, it is pro- 
bable that the fear of its bed effects may de- 
prive sodety of the advantages it might afford 
in this way. An arsenite of potash was ex- 
tensively used by the hite Dr Fowler of York, 
who published a treatise on it, in intermittent 
and remittent fevers. He found it extremely 
cfiicadous in periodical headache, and as a 
tonic in nervous and other disorders. Exter- 
nally it has been employed as a caustic to ex- 
tirpate cancer, combined with sulphur, with 
bole, with antimony, and with the leaves of 
cr o w f oo t ; but it always gives great pain, and 
is not unattended with danger. 

It baa been more lately used as an alteradve 
with advantage in chronic riieumatism. The 
sj m pUm is whidt show the system to be arwe" 



n^ed are, thickness, redness, and stiffness of 
the paipebr^, soreness of the gums, ptyalism, 
itching over the surface of the body, restless- 
ness, cough, pain at stomach, and headache. 
When the latter symptoms supervene, the ad- 
ministration of the medidne ought to be im- 
mediately suspended. It has also been recom- 
mended against chincough ; and has been used 
in consideiable doses, with success, to coun- 
teract the poison of venomous serpents. 

Since it acts on the animal economy as a 
deadly poison in quantities so minute as to be 
insensible to the taste when difiused in water 
or other vehicles, it has been oAen given with 
criminal intentions and fatal effects. It be- 
comes therefore a matter of the utmost in>> 
portance to present a systematic view of the 
phenomena characteristic of the poison, its 
operation, and consequences. 

1st, It is a dense substance, subsiding 
speedily after i^tation in water. I find its 
sp. gr. to vary from a728 to 3,730, which is 
a little higher than the number given above : 
72 parts dissolve in 1000 of boiling water, of 
which 30 remain in it after it cools. Cold 
water dissolves, however, only | ^%5 or -y^ 
of the preceding quantity. This water makes 
the syrup of violets green, and reddens litmus 
paper. Lime water gives a fine white pred- 
pitate with it of arsenite of lime, soluble in 
an excess of the arsenious solution : sulphi^ 
retted hydrogen gas, and hydrosulphuretted 
water, precipitate a golden yellow sulphuret 
of arsenic. By this means j ^^'c^t, of arse- 
nious acid may be detected in water. This sul- 
phuret, dried on a filter, and heated in a glass 
tube with a bit of caustic potash, is decom- 
posed in a few minutes, and converted into 
sulphuret of potash, which remains at the 
bottom, and metallic arsenic of a bright steel 
lustre, which sublimes, coating the sides of the 
tube. The hydrosulpburets of alkalis do not 
affect the arsenious solution, unless a drop or 
two of nitric or muriatic add be poured in, 
when the characteristic golden yellow predpi- t 
tate falls. Nitrate of silver is decomposed by 
the arsenious add,, and a very peculiar yellow 
arsenite of silver precipitates; which, however, 
is apt to be redissolved by nitric acid, and 
therefore a very minute addition of ammonia 
is requisite. Even this, however, also, if in 
much excess, rediasolves the silver predpitate. 
As the nitrate of silver is justly regarded a» 
one of the best predpitant tests of arsenic^ 
the mode of using it has been a subject of 
much discussion. The presence of muriate 
of soda, indeed, in the arsenical solution, ob- 
structs, to a certain degree, the operation of 
this reagent. But tliat salt is almost always 
present in the jfrimte via, and is an usual in- 
gredient in soups, and other vehicles of the 
poison. If, after the water of ammonia has 
been added, (by plunging the end of a glass 
rod dipped in it into the supposed pdsonoua 



ACID 



16 



ARSENIOUS. 



liquid), we dip another rod into a eolation of 
pure nitrste of silver, and transfer it into the 
anenious solution, either « fine yellow cloud 
will be formed, or at first merely a white curdy 
precipitate. But at the second or third im- 
mersion of the nitrate rod, a central spot of 
yellow will be perceived surrounded with the 
white muriate of silver. At the next im- 
mersion this yeUow cloud on the aurfiu^ will 
become very con^cuous. Sulphate of soda 
does not interfere in the least with the silver 
test. 

The ammonia^ulphatet or rather ammo- 
nia-acetate of copper, added in a somewhat 
dilute state to an arsenious solution, gives a 
fine grass-green and very characteristic preci- 
pitate. This green arsenite of copper, well 
washed, being acted on by an excess of sul- 
phuretted hydrogen water, changes its co- 
lour, and becomes of a brownish-red. Ferro- 
cyanate of potash changes it into ablood-red« 
Nitrate of silver converts it into the yellow 
arsenite of silver. 

Lastly, if the predpitato be dried on a filter, 
and placed on a bit of burning coal, it will 
diffuse a garlic odour. The cupreous test will 
detect ti^'ts^v ^ **>« weight of the arsenic 
in water. 

The voltaic battery, made to act by two 
wires on a little arsenious solution placed on 
a bit of window glass, developes metallic 
arsenic at the n^ative pole ; and if this wire 
be copper, it will be whitened like tombac. 

We may here remark, however, that Uie 
most elegant mode of using all tliese preci- 
pitation reagents is upon a plane of glass ; a 
mode practised by Dr Wollaston in general 
chemical research, to an extent, and with a 
success, which would be incredible in other 
bauds than his. Concentrate by heat in a 
capsule the suspected poisonous solution, 
having previously filtered it if necessary. 
Indeed, if it be very much disguised with 
animal or vegetable matters, it is better first 
of all to evaporate to dryness, and by a few 
drops of nitric acid to dissipate the organic 
products. Tlie clear liquid being now placed 
in the middle of the bit of glass, lines are to 
be drawn out from it in different directions. 
To one of these a particle of weak ammoniacal 
water being applied, the weak nitrate of silver 
may then be brushed over it with a hair penciL 
By placing the glass in different lights, either 
over white paper or obliquely before the eye, 
the slightest change of tint will be perceived. 
The ammonia-acetate should be applied to 
another filament of the drop, deut-acetate of 
iron to a third, weak ammonia-acetate of co- 
balt to a fourth, sulphuretted water to a fifUi, 
lime water to a sixth, a drop of violet syrup 
to a seventh, and the two galvanic wires at the 
opposite edges of the whole. Thus with one 
single drop of solution many exact experi- 
ments may be made. 



But the dhief, the decisive trial or aeperi- 
mentum crucis remaina, which is to take a Iktle 
of the dry matter, mix it with a small pinch 
of dry black flux, put it into a narrow glaaa 
tube sealed at one end, and after cleansing ito 
sides with a feather, urge ite bottom with a 
blowpipe till it be distinctly red-hot for a mi- 
nute : Hien garlic fumes will be smelt, and 
the sted4ustf ed coating of metallic arsenic will 
be seen in the tube about one-fourth of an inch 
above ita bottom. Cut the tube across at that 
point by means of a fine file ; detach the scale 
of arsenio witli the point of a penknife ; put 
a fragment of it into the bottom of a small 
wine-glass along with a few drops c^ ammo- 
nia^acetate of copper, and triturate them well 
together for a few minutes with a round-headed 
glass rod : Hie mazarine blue colour will soon 
be transmuted into a lively grass-green, while 
the metallic scale will vanish. Thus we dis^ 
tinguish perfectly between a particle of me- 
tallic arsenic and one of animalized charcoal* 
Another particle of the scale may be placed 
between two smooth and bright surftices qf 
copper, with a touch of fine oil ; and whilst 
they are firmly pressed together, exposed to 
a red heat : Tlie tombac alloy will appear as 
a white stain. A third particle may be placed 
on a bit of heated metal, and held a little 
under the nostrils, when the garlie odour will 
be recognized. No danger can be apprehended, 
as the fragment need not exceed the tenth of a 
grain. 

In cases of poisoning with arsenic, says 
Berzelius, the individual may have taken the 
deadly poison, either in the pulverulent fonn, 
or in a state of solution. In the first case, 
we can almost always detect visible particles 
of aisenic in the contents of the stomach, or 
on ita inner coat, where they are distinguisihed 
by dark red spota of inflammation, ^e fc4- 
lowing method will detect the nature of these 
particles, though less than one-tenth of a grain 
in weight. A glass tube, from one-tenth to 
one-seventh of an inch in diameter, is drawn 
out at one extremity into a fine point, from 
two to three inches in length, which part ought 
not to be wider internally than the thickness of 
a coarse knitting needle, and it is then her- 
metically closed at the end. Tlie particle of 
arsenic is moved downwards to the sealed 
point, and covered with charcoal powder: 
previously expose it to the flame of the blow- 
pipe, to drive off" any moisture. The char6oai 
is now healed to redness in the flame of a spirit 
lamp, and then the arsenic is brought under 
the influence of the heat, whidi, volatilizing itf 
makes it traverse the ignited charcoal, where* 
by it is reduced. The metallic arsenic con- 
denses beyond the force of the spirit flame, in 
the shape of a dark metallic ring, which, by 
gentle heating, can be driven further forward^ 
and thus more is accumulated, by which it ac- 
quires a higher lustre. Tlie small diameter of 
the tube preventa all circulation of air, so that 



ACID 17 ARSENIOU& 

no p«t of' the naetal is oildiied. It now re- heat, tilt all ia oxidated; whan it aMumas tha 

maina to detennina die anenic by its smelL form of sparldiog crystals, which may be as- 

This is cfiected if we cut the tube between the eertained by a microscope of four powers to 

cliaKCoai and tlie metal, then beat it gently in be octahedrons. 

Che place where the metal rest% while the nose It is to be obaerred, that one or two of tha 

is hM over it at a little distance. precipitation teats may be equivocal from ad- 

l¥bea the poisoning has been caused by the mixtures of Taiious substances. Thus tinc- 
aolution <tf arsenic, or by the substance in fine ture of ginger gives with the cupreous reagent 
poiwder, the contents of the stomach are to be a green predpitata ; and the writer of this ar- 
h e a t e d, or even boiled with caustic potash, tide was at first led to suspect from that ap- 
ancl then with muriatic add. The filtered peannce^ that an empirical tincture, put into 
fluid is reduced by evaporation; and, if ne- his hands for examination, did contain arsenic. 
cesaary, again filtered, and then subjected to But a careful analysis satisfied him of its ge- 
astream of sulphuretted hydrogen. Tbe fluid nuiiieness. Tea covers arsenic from the cu- 
is now heated to cause the precipitate to collect, preous test. Such poisoned tea becomes by its 
or evaporated, till it subsides. The sulphuret addition of an obscure olive or violet red, but 
of anenic is to be mixed with saltpetre^ and yields scarcely any predpitate. Sulphuretted 
defiagrated at tbe end of a hermetically sealed hydrogen, however, throws down from it a fine 
^asa tube. A little saltpetre is first melted yellow sulphuret of arsenic, 
ia tbe tube, and then small portions of the To remove tbe colouring matter of a ve- 
mixture are gradually dropped into it. The getable or animal kind, Mr Phillips has 
mass ia to be dissolved in as few drops of water very properly recommended to mix the poi- 
as poasible ; then lime water is to be added in soned liquid with well washed animal cluv- 
excess, and heated to boiling, by which the coal (bone-black), and thereafter to filter, be- 
aneniate of lime is more easily collected and fore applying the tests. 100 grains of black 
washed. Tho predpitate is collected, mixed mixed with 500 of port wine, containing one 
with fresh buned diarcoal powder, and put grain of arsenious add, became so deoolour- 
inla a gkss tubOy drawn out as above de- ed, as to admit of the application of tests. 
scribed, with its sealed end inflated into a A good way of obviadng all these sources 
very small bulb, in which tbe mixture is of fallacy is to evaporate carefully to dryness, 
made to lie. The tube is first gently heated, and expose the residue to heat in a glass tube. 
to drive off any moisture the mixture may The arseuic sublimes, and may be afterwards 
have abeocbed, and then the under point <^ operated on without ambiguity. M. Orfila 
the butt* is kept in the flsme of the blowpipe has gone into ample details on the modifica- 
wntil the glasa begins to melt. The arsenic tions produced by wine, coffee, tea, broth, &c. 
is now reduced and collected in the neck of on arsenical tests, of which a good tabular 
the bulb, where it is spread- over so small a abstract is given in Mr Hiomson's London 
surface that the sn^lest quantity may be Dispensatory. But it is evident that the dif- 
4letected. In fiict, one>tenth of a grain of ferences in these menstrua, as also in beers, 
sulphuret of arsenic is suffident to afford a are so great as to render predpitations and 
aatufiictory aad dedsive reduction test. — An- changes of colour by reagents very unsatis- 
ecbcr mode of treating sulphuret of arsenic is, factory witnesses in a case of life and deaths 
to intpoduce it into the narrow end of the Hence tbe method of evaporation above de- 
tube fint described, and to insert a piece of scribed should never be neglected. Should 
piane-finte wire (No. 1 1.), an inch in length, the arsenic be combined with oil, tbe mixture 
into tbe tube, so far as tbe suriace of the sul- ought to be boiled with water, and the oil 
phuvet. The steel wire is next to be heated then separated by the capillary action of wick- 
tn a ^irit of wine lamp, and the heat gradu- threads. If vritb resinous substances, these 
ally raised in such a manner that the sulphu- may be removed by oil of turpentine, not by 
ret, in tbe state of vapour, passes along the alcohol (as directed by Dr Black), which is a 
surfisoe of tbe glowing iron. In this way, good solvent of arsenious add. It may more- 
snlphuret of iron and sublimed metallic ar- over be observed, that both tea and coffee 
seme are obtained. Hie operation ought to should be freed from thdr tannin by gelatin, 
be conducted slowly. Iron-turnings will not which does not act on the arsenic, previous to 
answer, because the arsenic coinbines with the use of reagents for the poison. When one 
them vrithout any sublimation. The garlic part of arsenious acid in watery solution is 
smell should never be trusted to without ac- added to ten parts of milk, the sulphuretted 
tual reduction of tbe arsenic hydrogen present in the latter, occasions the 

For detecting the predse nature of tbe me- white colour to pass into a canary yellow ; the 

tallic crust of revived arsenic, when its quan- cupreous test gives it a slight green tint, and 

tity ia too minute for its physical characters tlie nitrate ofsilver produces no visible change, 

to be unequivocally ascertained, Dr Christison though even more arsenic be added ; but Sie 

has added a very elegant test, which was sug- hydrosulphurets throw down a golden yellow^ 

gested to him by Dr Turner. It consists in with the aid of a few drops of an add. The 

chasing the crust up and down the tube by liquid contained in the stomach of a rabbit poi- 



ACI0 



IS 



AR8ENIOUS. 



Mtted witb a lolutioD of 3 gnuns of afsenioiii 
add, aflforded a white precipitate with nitiwie 
of silvery grejrish-white with lime water, greeo 
with the aiimionifr4ulphatey and deep yellow 
with sulphuretted hydrogen water. 

The pEecediog copious description of the 
liabitudes of arsenious acid in different cir* 
comsfesnoesy is equally applicable to the solu- 
ble arKniteSt Their poisonous operation, as 
well as that of the arsenic acid, has been 
satisfactorily referred by Mr Brodie to the 
suspension of the functions of the heart and 
brain, occasioned by the absorption of these 
substances into the circulation, and thdir con- 
sequent determination to the nervous system 
and the alimentary canal. This proposition 
was established by numerous experiments on 
rabbits and dogs. Wounds were inflicted, 
and arsenic being applied to them, it was 
found that in a short time death supervened, 
with the same symptoms of inflammation of 
the stomach and bowels as if the poison bad 
been swallowed. 

He divides the morbid affections into three 
classes: Ist, Those depending on the nervous 
system, as palsy at first of the posterior ex- 
tremities, and then of the rest of the body, 
convulsions, dilatation of the pupils, and ge- 
neral insensibility : 2d, Those which indicate 
flisturbance in the organs of circulation ; for 
example, the feeble, slow, and intermitting 
pulse» weak contractions of the heart im- 
mediately after death, and the impossibility 
of prolonging them, as may be done in sudden 
deaths from other causes, by artificial re- 
spiration c 3d, Lastly, Those which depend 
on lesion of the alimentary canal, as the pains 
of the abdomen, nauseas, and vomitings, in 
those animals which were suffered to vomit. 
At one time it is the nervous system that is 
most remarkably affected, and at another the 
(vgans of circulation. Hence inflammation 
of the stomach and intestines ought not to be 
considered as the immediate cause of death* 
in the greater number of cases of poisoning 
by arsenic. However, should an animal not 
sink under the first violence of the poison, if 
the inflammation has had time to be de- 
veloped, there is no dcnibt that it may destroy 
life. Mr Earle states, that a woman who 
had taken arsenic resisted the alarming.sym]>- 
toms which at first appeared, but died on Uie 
fourth day. On opening her body, the mu- 
cous membrane of the stomach and intestines 
was ulcerated to a great extent Yet authen- 
tic cases of poison are recorded, where no trace 
of inflammation was perceptible in the prima 
vug. ' 

The effects oi anenic have been graphically 
represented by Dr Black : " The symptoms 
produced by a dang«x>us dose of arsenic begin 
to appear in a quarter of an hour, or not much 
longer, after it is taken. First sickness, and 
great distress at stomach, soon followed by 
&irst, and burning heat in the bowels. Then 



eome on violent vomiting and sevens co&c 
pains, apd excessive and painful purgiagk 
Hiis brings on fiiintings with cold sweats, and 
other signs of great debility. To this succeed 
painful cramps, and contractions of the Icga 
and thighs, and extreme weakness, and death." 
Similar results have followed the incautious 
sprinkling of schirrous ulcers with powdered 
arsenic, or the application of arseniad papteik 
The following more minute specification of 
symptoms is given by Orfila: ** An austere 
taste in the mouth; frequent ptyalism; conti- 
nual spitting ; constriction of the pharynx and 
Oiiophagus ; teeth set on edge ; hiccups ; nausea; 
vomiting of iNrown or bloody matter ; anxiety ; 
frequent fainting fits; burning beat at the 
prwcordia; inflanmiation of the lips, tongue^ 
palate, throat, stomach; acute pain of sto- 
mach, rendering the^ mildest drinks intoler- 
able ; black stools of an indescribable fetor ; 
pulse frequent, oppressed, and irregular*- 
somedmes slow and unequal; palpitation of 
the heart ; syncope ; unextinguishable thint ; 
burning sensation over the whole body, r^. 
sembling a consuming fire—at times an icy 
coldness; difiicult respiration; cold sweats; 
scanty urine, of a red or bloody appearance; 
altered ezpressioo of countenance; a livid 
circle round the eyelids ; swelling and itching 
of the whole body, which becomes covered 
with livid spots, or with a miliary eruption ; 
prostration of strength ; loss of feeling, espe^ 
dally in the feet and hands; delirium, co». 
vulsions, sometimes accompanied with an iop. 
supportable priapism ; loss of the hair ; sepa^' 
•ration of the epidermis ; horrible convulsions ; 
and death." 

It is uncommon to observe all these fti^t- 
ful symptoms combined in one individual; 
sometimes they are altogether wanting^ as ia 
shewn by the following case, related by M. 
Chaussier. A robust man of middle age swal* 
lowed arsenious add in large fragments, and 
died without experiencing other symptoms 
tlian slight syncojtes. On opening his sto^ 
mach, it was found to contain the arsenioua 
acid in the very same state in which he had 
swallowed it : There was no appearance what- 
ever of erosion or inflammation in the intear 
tinal canal. EtmuUer mentions a young girl'a 
bdng poisoned by arsenic, and whose stomach 
and bowels were sound to all appearance^ 
though the arsenic was found in Uiem. In 
general, however, inflammation does extend 
along the whole canal, from the mouth to 
the rectum. Tlie stomach and duodenuv^ 
present frequently gangrenous points, eschars^ 
perforations of ail their coats; the villous 
coat in particular, by this and all other cor- 
rosive poisons, is commonly detached, as if it 
were scraped off or reduced into a paste of s 
reddish-brown colour. From these considers- 
tions we may conclude, that from the eiist- 
ence or non-existence of intestinal lesions, 
from the extent or seat of the symptoms alone. 



ACID 19 BKNZOIC. 

the pbjsicuin should not venture to pnmounce by tickling tbe finico with a ftnther. Cljr«- 

SefinitiYely on the fact cf poisonnig. ^ ten of a similar nature may be also employed. 

Tlie result of Mr Brodie*s experiments on ' Many persons have escaped death by having 

bralcs teaches, that the inflammations of the taken the poison mixed with rich soups; and 

intestines and stomach are more severe when it is well known, that when it is prescribed 

die poison has been applied to an external as a mecBdne^ it acts most beneficudly when 

wound, than when it has been tfardwn into tha given soon after a meaL These facts have 

stomadi itself. led to the prescription of butter and oLh; the 

The best remedies against this poison in the use of which is, however, not advisable^ as 

aammarh axe copious draughts of bland liquids they screen the arsenical particles from moi« 

of a mucilaginous consistence^ to inviscate proper menstrua, and even appear to aggravate 

the povrder, so as to procure its -complete its virulence. Morgagni, in his great work 

cjectioD by vomiting. Sulphuretted hydrogen on tbe seats and causes of disease, states, that 

randenaed in water is the only direct antidote at an Italian feast the dessert was purposely 

to its virulence; Orfila having found, that sprinkled over with arsenic instead. of flour* 

when dogs were made to swallow that h'quid. Those of the guests who had previously ata 

after getting a pmsonous dose of arsenic, they and drank little, speedily perished ; those who 

recovered, though their oesophagus was tied had their stomachs well filled, 'were saved by 

Is prevent vomiting ; but when the same dose vomiting. He also mentions the case of three 

«f poison was administered in the same cir- children, who ate a vegetable soup poisoned 

eomstancesy without the sulphuretted water, with arsenic One of them, who took only 

that it proved fataL two spoonfuls, had no vomiting, and died; 

'When the viscera are to be subjected after the other two, who had eaten the rest, vo- 

deatfa to chemical investigation, a ligature mited, and got well. Should the poisoned 

eogfat to be tinrown round the oesophagus and patient be incapable of vomiting, a tube of 

the beginning of the colon, and the interme- caoutchouc, capable of being attached to a 

diate stomach and intestines removed, llieir syringe, msy be had recourse to. The tube 

liquid contents should be emptied into a and pump serve to introduce the drink, and to 

basin ; and thereafter a portion of hot water withdraw it after a few instants, 

introduced into the stomach, and worked tho- It has been for some time known in Ger- 

roughly up and down this viscust as well as many, that the bodies of persons poisoned with 

die intt8tine& arsenic have been found, after several month% 

After filtration, a portion of the liquid nay, two years and a half, in a state of re- 
should be concentrated by eviqioration in a markable preservation, or converted externally 
porcelain capsule, and then submitted to the into a species of adipocerous matter; and tha 
proper reagents above described. We may stomach and intestines firm, flexible^ veddish» 
also endeavour to extract from the stomach, as if they had been pickled in brine ; and the 
by digestion in boiling wster with a little appearances of disease, caused by the arsenic^ 
amnxmii^ the arsenical impr^^tion, which were often as distinct as in a recent body^ 
has been sometimes known to adhere in mi- Dr Christison has verified these results by ex- 
nute particles with wonderful obstinacy. This periments on dogs. Dr Kelch, of Konigsbeig, 
precaution ought therefore to be attended to. buried, in February, the internal organs of a 
Hie heat will dissipate the excess of ammonia man who had died of arsenic, and whose body 
in tlie above operation ; whereas by adding had remained without burial till tbe external 
potash or soda, as prescribed by the German parts had begun to decay ; and on examining 
diemistsy we introduce animal matter in al- the stomach and intesdnes, five months after* 
kaHne solution, which complicates the inves- wards, he found that the hamper which con* 
tigatioD. tained them was very rotten, but that they had 

The matters rejected ftom tbe patient's a peculiar smell, very different from tlwt of 

boweb before death should not be neglected, putrid bowels, were not yet acted on by pu* 

These, geoerally speaking, are best treated trefaction, and were still as fresh as when they 

by caudous evaporadon to dryness ; but we were taken from the body, and might have 

must beware of headng the residuum to served to make instrucdve preparadons. In 

400^, since at that temperature, and perhaps the stomach, the inflamed spots seen origi- 

a Utde under it, the arsenious add itself sub- nally had not disappeared. In consequence 

of this preservadon of the body, arsenic has 



Vinegar, bydrogturetted alkaline sulplmrets, been detected in Geaoany fourteen vunUks 

and oils, are of no use as counterpoisons. after interment* This preservadve power is, 

Indeed, when the arsenic exists in substance however, subject to excepdons, the causes of 

in the stomach, even sulphuretted hydrogen which have not been investigated. 
water is of no avail, however effectually it ACID (B£NZOIC). The usual method 

neotn^xe an arsenious solution. Syrups, lin- of obtaining this add aflbids a very elegant* 

seed tea, decoction of mallows, or tragacanth, and pleasing example of the chemical proceas 

and warm milk, should be administered as of sublimation. For this purpose a thin stra- 

eopiously as possible, and vomiting provoked turn of powdered benzoin is spread over the i 



ACID 20 BENZOIC. 

boCtcMti af a glased earthen pot, to which a tall the decoctionsy being mixed together, moat be 

eonical paper covering is fitted : gentle heat evaporated to two pounds, and stxained int(» 

is then to be applied to the bottom of the pot, a glass vessel. 

which fuses the benxoin, and fills the apart- • This fluid consists of the acid of benzoin 

ment with a fragrant smell, arising from a combined with lime. After it is become 

portion of essential oil and add of benaoiny cold, a quantity of muriatic acid must be 

which are dissipated into the air ; at the same added, with constant stirring, undl the fluid 

time the add itself rises very suddenly in the tastes a little sourish. During this time the 

paper head, which may be occasionally ii»> last-mentioned acid unites with the lime^ and 

specCed at the top, though with some Kttle forms a soluble salt, which remains suspend- 

care, because the fumes will exdte coughing, ed, while tlie less soluble add of benzdn,. 

Thi» add sublimate is condensed in the form bdng disengaged, falls to the bottom ia 

of long needles, or straight filaments of a white powder. By repeated aflusions of cold water 

colour, crossing each other in all directions, upon the filter, it may be deprived of the 

When the white add ceases to rise, the cover muriate of lime and muriatic add with which 

may be changed, a new one applied, and the it may happen to be mixed. If it be requir- 

heat raised: more flowers ofa yellowish colour ed to have a shining appearance, it may be 

will Uien rise, which require a second sub- dissolved in a small quantity of boiling water, 

limation to deprive them of the empyreumatic from which it will separate in silky filamenta 

oil they contain. by cooling. By this process the benxoic acid. 

The sublimation of the add of benzmn may may be procured from other substances in 

be conveniently performed by substituting which it exists. 

an inverted earthen pan instead of the paper • Mr Hatchett has shown, that, by digesting 

cone. In tliis case the two pans should be benzoin in hot sulphuric add, very b^utiful 

made to fit, by grinding on a stone with sand, crystals are sublimed. This is perhaps the 

and they must be luted together with paper best process for extracting the add. If we 

dipped in paste. This method seems pre- concentrate the urine of horses or cows, and 

fen^le to the other, where the presence of the pour muriatic acid into it, a copious fNrecipi- 

operator is required elsewhere ; but the paper tate of benzoic add takes place. This is the 

bead can be more easily inspected and cfaang- cheapest source of it. 

ed. The heat applied must be very gentle^ Benzoic add has been found by M. Vogel 

and the vessels ought not to be separated till in the sweet-scented vernal grass (anthoxan- 

they have become cool. thum odoratum), and in the sweet-scented 

' The quantity of acid obtained by these |oft grass (holcus odoratxis); two grasses 

methods differs according to the management, which communicate to hay their peculiar 

and probably also from difi*erence of purity, aroma. 

and in other respects, of the balsam itself. Tlie add of benzoin is so inflammable,. 
It usually amounts to no more than about that it. bums with a clear yellow flame with* 
one-dghth pait of the whole wdght. Indeed out the assistance of a wick. The sublimed 
Sdieele says, not mT>re than a tenth or twelfth, flowers in thdr purest state, as white as or- 
TTie whole add of benzoin is obtained with dinary writing paper, were fused into a clear 
greater certainty in the humid process of transparent yellowish fluid, at the two hun^ 
Scheele : this consists in boiling the powdered dred . and thirtieth degree of Fahreohdt*s 
balsam with lime and water, and afterwards tliermometer, and at the same time began 
separating the lime by the addition of muria- to rise in sublimation. It is probable that 
tic add. Twelve ounces of water are to be a heat somewhat greater than this may be 
poured upon four ounces of slaked lime ; and, required to separate it from the resin. It is 
after the ebullition is over, eight pounds, or strongly disposed to take the crystalline form 
■inety-dx ounces, more of water are to be in coolmg. Tlie concentrated sulphuric and 
added : a pound of finely powdered benzoin nitric adds dissolve this concrete acid, and 
being then put into a tin vessel, six ounces of it is again separated without alteration, by 
the milk of lime are to be added, and mixed adding water. Other acids dissolve it by the 
well with the powder; and afterwards tlie rest assistance of heat, from which it separates by 
of the lime water in the same gradual manner, cooling, unchanged. It is plentifully solu- 
because the benzoin would coagulate into a ble in ardent spirit, from which it may like- 
mass, if the whole were added at once. This wise be separated by diluting the spirit with 
mixtuae must be gently boiled for half an water. It readily dissolves in oils, and in 
hour with constant agiution, and afterwards melted tallow. If it be added in a small 
sufiered to cool and subside during an hour, proportion to this last fluid, part of the tal- 
The supernatant liquor must be decanted, low congeab before the rest, in tlie form of 
and the residuum boiled with dght pounds white opaque clouds. If the. quantity of acid 
more of lime water ; af^ which the same be more considerable, it separates in part by 
process is to be once more repeated : the re- cooling, in the form of needles or feathers, 
maining powder must be edulcorated on tlie In the destructive distillation of tallow, ben- 
filter by aflusions of hot water. Lastly, all zoic acid is said to be formed 



ACID 21 BORACIC 

At die temperature of boiling water, oil of and ail the bases. The solutions of all the 

tvipcntiae diMolTes about its own weigfat of benxoates, when drying on the sides of a ve»^ 

benaoic acid, but the solution becomes con- sel wetted with them, form dendritical crystal- 

cieCe on cooling. lizations. 

Viae benaoic acid is in the form of a light TVommsdorff found in his experiments, 

^wder, evidently crystalliied in fine needles, that benaoic add united readily with metallic 

the figure of which is difficult to be deter- oxides. 

mined from their smallness. It has a white The beiuoates are all decomposable by 
and shining appearance ; but when oontami- beat, which, when it is slowly applied, first 
nated by a portioa of Tolatile oil, is yellow separates a portion jo€ the acid in a vapour 
or brownish. It is not brittle, as might be that condenses in crystals. The soluble ben- 
expected firom its appearance, ' but has rather loates are decomposed by the powerful acids, 
a kbd of ductility and elasticity, and, on which separate their add in a crystalline form, 
nibbing in a mortar, becomes a sort of paste. The benzoate of ammonia has been proposed 
Its taste is acrid, hot, aridulous, and bitter* by Beraelius as a reagent for predpitating 
It reddens the infusion of litmus, but not red oxide of iron from perfectly neutral solu- 
sfrup of violets. It has a peculiar aromatic tions. See Salts (Table of.) 
smell, but not strong unless heated. . This, ACID (BOLETIC). An add extracted 
however, appears not to belong to the add ; from the expressed juice of the boletut p$eudo~ 
fbr BL Giese Informs us, that on dissolving igmoriu* by M. Braconnot. This juice^ con- 
the benaoic acid in as litde alcohol as possi- centrated to a syrup by a very gentle heat, 
ble^ filtering the solution, and predpitating by was acted on by strong alcohol. What re- 
water, the add will be obtained pure, and void * mained was dissolved in water. When ni- 
of smell, the odorous oil remaining dissolved trate of lead was dropped into this solution, 
ra the spirit. Its spedfic grayity is 0.667. It a white predpitate feU, which, after being 
is not perceptibly altered by the air, and has well washed with water, was decomposed by 
been kept in an open vessel twenty years with- a current of sulphuretted hydrogen gas. Two 
out lodng- any of its wdght. None of the difi*erent adds were found in the liquid after 
eombuslible substances have any effect on it ; filtration and evaporation. One in penna> 
but It may be refined by mixing it with char- nent crystals was sOLEnc add; the other 
coal powder and subliming, b«ng tims ren- was a small proportion of phosphoric add. 
dered much whiter and better crystallized. It The former was purified by solution in ako- 
Is not very soluble in water. Wenzel and hoi, and subsequent evaporation, 
liditenstcih say four hundred parts of cold It consists of irregular four-sided prisma, 
water dissolve but one, though the same of a white colour, and permanent in the air. 
quantity of boiling water dissolves twenty Its taste resembles cream of tartar. At the 
parts, nineteen of which separate on cooling, temperature of 68^ it dissolves in 180 times 
- Berselius states the composition of benzoic its wdght of water, and in 45 of alcohoL 
acid to be, caibon 74>.41, oxygen 20.43, and Vegetable blues are reddened by it Red 
h ydr ogen &I6, in 100. From the benzoate oxide of iron, and the oxides of silver and 
of lead, he deduces the prime equivalent to mercury, are precipitated by it firom their 
be 14.893. By my experiments its compo- solutions in nitric acid ; but lime and baryta 
nents are, caibon 66.74^ oxygen 28.32, and waters are not affected. It sublimes when 
hydrogen 4u94; and by saturation with am- heated in white vapours, and is condensed in 
monia its prime equivalent appeared to be a white powder.— ^nn. de Chimie, Ixxx. 
I4w5, to oxygen 1. ACID (BOMBIC). An add which M. 
The benzdc acid unites without much Chaussier extrscted firom the silk worm in 
difficulty with the earthy and alkaline bases. 1781. 

The benzoate of baryta is soluble and ACID (BORACIC). The salt composed 

crystallizes. Hiat of lime is very soluble in of this add and soda had long been used, both 

though much less in cold than in hot, in medidne and the arts, under the name of 



and crystallizes on cooling. The benzoate of borax, when Homberg first obtained the add 

magnesia is soluble, crystallizable, and a littie separate in 1702, by distilling a mixture of 

deliquescent. That ofalumina is ver}* soluble, borax and sulphate of iron. Lemery the 

crystallizes in dendrites, is deliquescent, and younger soon aiter discovered that it could be 

has an acerb and bitter taste. The benzoate obtained from borax equally by means of the 

of potash crystallizes on cooling in litde com- nitric or muriatic acid. Geofiroy detected 

pscted needles. The benzoate of soda is very soda in borax ; and at length Baron proved 

crystallizable, very soluble, and not deliques- by a number of experiments, that borax is a 

cent like that of potash, but it is decomposable compound of soda and a peculiar acid, 

by the same means. It is sometimes found To procure the add, dissolve borax in hot 

native in the urine of graminivorous qua- water, and filter die solution ; then add sul- 

drupcds, but by no means so abundantiy as phuric acid, by litUe and little, till the liquid 

that of lime. Tlie benzoate of ammonia is has a sensibly acid taste. Lay it aside to 

volatile, and decomposable by all the adds cool, and a great number of small shining 



. ACID 2t BQRACIC. 

kminated crystals will finrm. These are the The prime equivalent of boracic acid has 

boradc actd» lliey are to be washed with been inferred, from the borate of ammoniAy to 

cold water^ and drained upon paper. be about 2.7 or 2.8 ; oxygen being 1.0; and 

Boracic add thus procured is in the form it probably consists of 2.0 of oxygen -f*^® ^ 

of thin irregular hexagonal scales* of a silvery boron. But by MM. Gay Lussac and llie- 

whiteness, having some resemblance to sper* nard, the proportions would be 2 of boron tp 

maoeti, and the same kind of greasy feeL It 1 of oxygen. 

has a sourish taste at first, then mokes a bit- Boracic acid has a more powerful attraction 

terish cooling impression, and at last leaves for lime than for any other of the bases, 

an agreeable sweetness. Pressed between though it does not readily form borate of lime 

the teeth, it is not britde but ductile. It has by adding a solution of it to lime water, or 

no smell ; but when sulphuric acid is poured decomposing by lime water the soluble alkn? 

on it, a transient odour of musk is produced, line borates. In either case an insipid white 

Its specific gravity in the form of scales is powder, nearly insoluble, which is the borate 

1.479; after it has been fused, 1.803. It is of lime, is however precipitated. The borate 

not altered by light Exposed to the fire, it of baryta is likewise an insoluble, tasteless 

swells up, from losing its water of crystal- white powder. 

lisation, and in this state is called calcined One of the best known combinations of this 

boracic add. It melts a little before it is add is the native magnesia4xirate of Kalk^ 

red-hot, without perceptibly losing any water, berg, near Lunenburg. See Boeacxte. 

but it does not flow freely till it is red, and The borate of potash is but little knomu 

then less than the borate of soda. After this With soda the boradc add forms a salt of 

fusion it is a hard transparent glass, becom- ' considerable use in the arts, and long known 

ing a little opaque on exposure to the air, by the name of borax. 

without alwtracting moisture from it, and uiv- M. Fayen has lately described a variety of 

altered in its properties; for on bdng dis- borax which crystallises in regular octahe- 

Golved in boiling water it crystallizes as b&> drons, is harder than common borax,, and is 

fore. This glass is used in the composition almost as sonorous as cast-iron. Its fracture 

of fiilse gems. is vitreous, and rather undulated. It differs 

Boiling water scsrcely dissolves one-fiftieth little from common borax, except in contain- 
part, and cold water much less. When this ing less water of crystallization, and is there* 
solution ia distilled in close vessels, part of fore preferred in Pmn for soldering copper, 
the acid rises irith the water, and crystallizes It is prepared by subjecting sc^ution of com- 
in the recdver. It is more soluble in alcohol ; mon borax to ebullition, and then allowing it 
and alcohol containing it burns with a green to cool and crystallise. Borax is to be dia- 
flame, as does paper dipped in a solution of solved in water at 212^ Fahr. in such quan!«> 
boradc add. tity as to give e solution of specific gravity 

Crystallized boradc add is a compound of 1.246. When left to cool dowly and re^gu* 
67 parts of acid and 43 of water. The honour larly, small octahedral crystals begin to fbnn 
of discovering the radical of boracic add is at the temperature of 174*> F., which inc rease 
divided between Sir H. Davy and MM. Gay in number and size till the temperature is 
Lussac and Thenard. The first, on applying 133^. If the mother liquor be now decantr 
his powerful voltaic battery to it, obtained a ed, all the crystals left are of the kind before 
chocolate-coloured body in small quantity ; described ; but nearly all the crystals formed 
but the two latter chemists, by acting on it under this heat are borax of the ordinary 
and potassium in equal quantities, at a low red sort. If the density of the boiling solutidn be 
heat, formed boron and sub-borate of potash, no higher than 1.170, only common crystals 
For a small experiment, a glass tube will serve, are obtained. Hius tlie one or other kind 
but on a greater scale a copper tube is to be may be obtained at pleasure, 
preferred. The potassium and boradc acid, According to M. Arfwedson, borax con* 
perfectly dry, should be intimately mixed sbts, inthe dryorcaldnedstate, of add68.9^ 
before exposing them to heat On withdraw, soda 31. 1, in 100. It was analyzed by mix- 
ing the tube from the fire, allowing it to cool, ing it with three or four times its weight of 
and removing the cork which loosely closed its finely powdered fiuor-spar, free from silica, 
mouth, we then pour successive portions of and a sufiicient quantity of sulphuric add. 
water into it, till we detach or dissolve the On evaporating the mixture, and exposing it 
whole matter. The water ought to be heated to a red heat, all the boradc add was expelled 
each time. The whole collected liquids are as fluoboric add gas, and from the resultii^ 
allowed to settle ; when, after washing the sulphate of soda Uie quantity of this alkaline 
predpitate till the liquid ceases to affect syrup base was inferred. 

of violets, we dry the boron in a capsule, and Groelin found borax to contain in the crys- 

then put it into a phial out of contact of air. uUized state 40.6 per cent of water ; and in 

Boron is solid, tasteless, inodorous, and of a the dry state he regards it as a compound of 

greenuh-brown colour. Its spedfic gravity two parts by weight of add and x>ne of base, 

b somewhat greater than water. Borax^ therefore, inste«d of being called, ms 



ACID 28 BUTYEIC. 

the sub-bente of soda* ihould be cuhy on eontect with light, is thereby dis- 

vieved m e bi^Mrate. tioguithed team bromide of tUver, which is 

• RnoD M. Arfwcdson's anelyvs the prime yeIiowish» curdy, and easily affected by the 

tqsindeiit at boncic add would seem to be soDbeaois. 

4^4^ sad ftem M. Gmelin's 4v Dr Tbomsoii The salts of lead, which produce an abun- 

h only Sb More recently M • Soebei*' dant ciystalline precipitate with hydrobromate 

Unds borax to consist of add 67.584^ of potMh, have no e^ct on the bromata. 
32l416; whence the eipnYalent of boi*- Bromate of baryta forms adcular erystab, 

cie TMJ oomes oat 4b 175. soluble in boiling water, scarcely so in cold 

If. I^cn fiMiBd 100 parts of prismatic water, and melting with a green flame on 

bans to contain 46b95 of water ; anid 100 of burning cools. 
the «clebadial 30i64 of water. He gives the On pouring dilute sulphoric add into the 



itntion of these salts as ibUows:'*- solution of bromate of baryta, so as to pred* 

Aahyd^Bat, Fiimii.Sor. Octahed. Bor. . pttate the whole of the base, a dilute solution 

Bar ^*2^88 ^*?L 88 2^88 of biomic add is obtained. Hie bromate of 

Sodi,*** 1 = 39.0^ 1= 39.09 1 = 39.09 ^'^ ?» »«J *'?'*^^1^' ^IIT".*'^ 

W^. 10=112143 5 = 56.217 fomtoung dilonne with brome, and by plao- 

* . — ' .^ :; ing this compound in contact with a solution 

127,09 239.52 183.307 ofthat earth. 

Borate of ammonia forms in small rbom- 3y g]ovp evaporation the graater part of the • 

boidal crystals, essily decomposed by fire ; or crater may be remov^ It then acquires a 

m scales, of a pungent urinous taste, which syrupy consistence^ If the temperature be 

lose the oTstalUne fonn» and grow brown on raised higher with the view of expelling the • 

csposure to the air. water completely, one portion of the add ev*- 

Borate of baryta, when melted, and then pontes, and the other is decomposed into 

cut and polished, exhibits a high degree of oxygen and brome. The same change seems 

hutre^ and closely resembles the topas of toensue when the concentration is p^hed too 

Sszooy. ^ far by the abtion. of a surface of sulphuric 

Boiadc add unites with silex by fusion, add in vacuo. Water thus appears to be 

snd forma with it a solid and permanent vi- necessary to the constitution of bromic add. 

trsous compound. This add first reddens litmus paper, and - 

Boradc acid has been found in a disengag- soon thereafter deprives it of colour. It has 

ed state in sevend lakes of hot mineral waters scarcely any smelL Its taste is very add, but 

near Monte Rotondo, Berchiaio, and Cas- not at all corrosive. 

telloouovo in Tuicany, in the proportion of The hydradds, as also those which are not 

nearly nine grains in a hundred of water, by saturated with oxygen, act with great eneigy 

M. Hoeffer. Bf. Mascagni also found it ad- on bromic acid. Hie sulphurous, muriatic, 

hering to sdiistus, on the borders of lakes, hydriodic, and hydrobromic adds decompose 



of an obscure white, yellow, or greenish co- it, as well as sulphuretted hydrogen. From 

lour, and crystallised in the form of needles, hydriodic acid, compounds of brome with 

He baa likewise found it in combination with chlorine and iodine result, 
ammonia. See Salt. Bromic add appears to be compos e d , in 

ACID (BROMIC). When brome is agi- 100 parts, of 64.69 brome, 
tetod with a sufficiently concentrated solution 35.31 oxygen. 

of potash, two very different compounds are If it contain, like the chloric add, 5 atoms of 

fsnaed. Hydrobromate of potash remains, oxygen, the atomic weight of brome would 

dissolved in the liquid. A white powder pre- thus be 9. 1 ; but other experiments seem to 

ripitatea to the bottom of the vessel, of a crys- make it 9.5 ; whence the add should consist 

talliae aspect, which fuses on red-hot coals of 65.52 brome -f- 34.48 oxygen, 
like nitre, and is transformed by heat into ACID (OF THE BUG). This add is 

bromide of potassium, with the disengage- merely mentioned by Thenard, as a peculiar 

Dent of oxygen. This crystalline powder is compound. 

bromate of potash. It is scarcely soluble in ACID (BUTYRIC). We owe the dis- 

skohol* but in boiling water it dissolves pretty covery of this add to M. Cbevreul. Butter, 

eopioaaly, from which solution, by cooling, he says, is composed of two firt bodies, analc^ 

there fall down needles grouped together, gous to those of bog*s-iard, of a colouring 

When crystallised by evaporation, the bro- principle, and a remarkably odorous one, to 

■ute is deposited in crystalline plates, with which it owes the properties that distinguish 

little lustre. It deflagrates on ignited char- it from the fats, properly so called. This 

aal ; and, when mixed in powder with sub- prindple^ which he has odled butyric add, 

limed sulphur, it detonates on being struck forms well characterised salts with baryta, 

by a hammer. strontia, lime, the oxides of copper,, lead, 

The solution of this salt yields a precipitate &c. ; 100 parts of it neutralise a quantity of 

irith nitrate of silver. This white and pul- base which contains about ten of oxygen. M. 

verulent predpitate, blackening with difii- Chevreul has not explained his method of 



ACID 



9^ 



CARBAZOTIC. 



separating tliit acid from the other ooMti- 
tuents of butter. ^ See Joum. de Pharmacies 
iii. 80. 

ACID (CAMPHORIC). One part of 
camphor being introduced into a glass retort, 
four parts of nitric acid, sp. gr. 1.^ are to be 
poured on it, a receiver adapted to the retort, 
and all the joints well luted. Hie retort is 
then to be placed on a sand heat, and gradu- 
ally heated. During the process a consider- 
able quantity of nitrous gas, and of carbonic 
add gas, is evolved ; and part of the camphor 
is volatilised, while another part seises the 
oxygen of the nitric add. When no more 
vi^wurs are extricated, the vessels are to be 
separated, and the sublimed camphor added 
to the add that remains in the retort. A like 
quantity of nitric add is again to be poured 
on this, and the distillation repeated. "Diis 
operation must be repeated till the camphor 
is completely acidified. Twenty parts ci 
nitric add are suffldent to ad^y one of 
camphor. 

When the whole of the camphor is addified, 
it crystallises in the remaining liquor. Hie 
whok is then to be poured out upon a filter, 
and washed with distilled water, to carry off 
the nitric add it may have retained. The 
most certain indication of the acidification of 
the camphor is its crystallising on the cooling 
of the liquor remaining in the retort 

To purify this add it must be dissolved in 
hot. distilled water, and the solution, after 
bdng filtered, evaporated nearly to half, or 
till a slight pellicle forms; when the cam- 
phoric add will be obtained in crystals on 
cooling. 

Camphoric add has a slightly add bitter 
taste, and reddens infusion of litmus. 

It crystallizes ; and the crystals upon the 
whole resemble those of muriate c^ ammonia. 
It effloresces on exposure to the atmosphere ; 
is not very soluble in cold water ; when placed 
on burning coals, it gives out a tiiick aromatic 
amcke^ and is entirely dissipated ; and with a 
gentle heat melts, and is subUmed. It is so- 
luble in alcohol, and is not precipitated from 
it by water ; a property that distinguishes it 
from the benzoic add. It unites easily with 
the earths and alkalis. See Salts (Table 
or). 

ACID (CAPRIC). An add obtained by 
Chevreul from the soap made with the butter 
of cow's milk, and so named because it has a 
smdl like that of a goat. At 5° Fahr. it 
exists in the form of crystals. At 65^ F. its 
sp. gr. is 0.910 ; 100 parts water dissolve only 
CL 12, but with alcohol it combines in all pro- 
portions. 

ACID (CAPROIC). An add similar to 
the preceding, and obtained from the same 
source. 

Its prime equivalent in the crystalline state 
aeems to be about 1 1. 

ACID (CARBAZOTIC). To obtain 



pure caifaaaotic add, says BI. lidicg its di^ 
coverer, the finest indigo is to be cnish^ and 
heated moderately, with dght or ten timea it» 
wdght of nitric add : it dissolves with effer- 
vescence, and produces much nitrous vapour. 
When the scum has fallen, it is to be boiled* 
and firesh add added, until no more nttraua 
vapour be exhaled ; in which case ndtlier 
resin nor artifidal tannin is produced* When 
the liquid cools, hard^ yellow, transparent 
crystals form, which are to be taken out and 
washed. They are to be dissolved in boiling 
water, and the few drops of crfeaginous liquid 
on the surface are to be removed with bibu> 
lous paper. By filtration and cooling a large 
quantity of brilliant yellow lamellar crystala 
are obtained. These are to be then dissolved 
in boiling water, and saturated with carbonate 
of potash, so as to obtain the carbaaotate of 
this base by cooling the liquor. This salt must 
be purified by repeated crystallizations. Its 
solution will ^en afford, with sulphuric, nitri^ 
or muriatic add, brilliant, dear, yellow crys- 
tals in plates, mostly triangular, which are the 
pure add. Four parts of the best indigo yield 
one of carbazotic add. 

Tlie carbaaotate of lead is readily formed 
from the pure add and carbonate of lead. 
It is a yellow powder, scarcely soluble in 
water, and, when dry, detonating strongly bj 
heat or percussion. It has indeed been pre- 
posed for the discharge of percussion guna. 
Carbaaotate of copper crystallises in long 
rhombic needles of an emerald-|;reen ocrfour ; 
whidi are soluble in water, and in air fo- 
resee, becoming yellow. 

The composition of carbazotic add is thus 
given by M. Lieb^ :— > 

Qubon, 35.043 

Azote, 16.167 

Oxygen, 4&790 

100.000 
Carbaaotate of mercury is a compound of 
53.79 add -|- 46.21 protoxide of the metal. 

Carbazotic acid is but slightly soluble in 
cold, but much more so in boiling water ; and 
the solution has a bri^t ydlow colour, red- 
dens litmus, has an extremdy bitter tssle^ 
and acts like a strong add on metallic oxidea* 
dissolving them, and forming peculiar salts^ 
Ether and alcohol dissolve the add readily. 

When fused in contact with chlorine or 
iodine, it is not decomposed, nor dOes solutioq 
of chlorine affect it. Cold sulphuric add has 
no action on it ; hot dissolves it ; but water 
separates the substance without alteration. 
Boiling muriatic add does not affect it ; and 
nitro-muriadc acid only with great diflSculty. 
These results shew that no nitric acid is pre- 
sent in iL 

Carbaaotate of potash crystallizes in long 
yellow quadrilateral needles, semitransparent 
and very brilliant : it dissolves in 260 parts of 
water at 59 F., and in much less of boiling 



ACID 26 CARBONIC. 

>; indeed, a i«tiintedboi]iog hot solution atmosphei^ and at alow temperature^ absorba 

bcco m w oo cooling a jdiam masB of needles, somewhat more than its bulk of fixed air, and 

firom wfaicfa scarcely any fluid will run. then appears acidulous. If the pressure be 

When a little b gradually heated in a glass greater, the absorption is augmented* It is to 

tHh^ it first fuses, and then suddenly explodes) be observed, likewise, that more gas than the 

faraaking the tube to fragments, in which traces water will absorb, should be present. Heated 

of cha r coal are observable. Hie slight solu- water absorbs less ; and if water impregnated 

bility of this salt, offersan easy method of tea- with this acid be exposed on a brisk fixe, the 

ting and separating potash in a fluid. Tho rapid escape of the aerial bubbles affords an 

saturated sc^ution of salt at 59^ F. is not dis- appearance as if the water wereat the point of 

tubed by muriate of platinum. It contains boiling, when the heat is not greater tlian the 

so water of crystallisation. Its constituents hand can bear. Congelation separates it readily 

are^ Carbaaotic acid» 83.79 and completely from water ; but no degree of 

Potash, 16.21 cold simply has yet brought this acid to a state 

— — of fluidity. 

100.00 Carbonic add is denser than common air, 

Oobaaotate of soda crystallises in fine silky in the proportion of 1.5277 to 1.0000; and for 

ydkyw needles, haying the general properties this reason occupies the lower parts of such 

of the salt of potash, but soluble in from 20 mines or caverns as contain materials which 

Id 24 parts of water at G09 F. afford it by decomposition. The miners call 

- Csrbaxotate of ammonia forms very long, it choke-damp. The Grotto del Cano, in the 

fisttened, brilliant, yellow crystals, very soluble kingdom of Naples, has been famous for ages 

in water. Carbaaotate of baiyta is obtained on account of the effects of a stratum of fixed 

by heating the carbonate of this earth in dilute air which covers its bottom. It u a cave or 

caibaaotic add. It crystallises in quadran- hole in the side of a mountain, near the lake 

gnbr prisms of a deep colour, which dissolve Agnano^ measuring not more than eighteen 

cMily in water. When heated it fuses, and is feet from its entrance to the inner extremity ; 

decomposed with very powerful explosion, ac- where if a dog or other animal that holds down 

companied with a vivid yellow flame. The its head be thrust in, it is immediately killed 

explosion reseoibles that of fulminating silver, by inhaling this noxious fluid. 

100 parts of die crystallized barytic salt consist Carbonic acid gas is emitted in large quan- 

of add 69. 16, baryta 21.60, and water 9.24. titles by bodies in the state of the vinous fer- 

C^otbasotate of lime, obtained like that of mentation, (see Fermentation) ; and on ecu 

baryta, is in flattened quadrangular prisms, count of. its great wdght, it occupies the 

very soluble in vrater, and detonating like the apparently empty space or upper part of the 

salt of potash. vessels in which the fermenting process is 

Caitiaaotate of silver is made by dissolving going on. A variety of striking experiments 

the oxide of the metal in the hot dilute acid ; may be made in this stratum of elastic fluid, 

and on gradual eraporation of the liquid, starry lighted paper, or a candle dipped into it, is 

gitmps of fine sdcuter crystals, of the colour immediately extinguished; and the smoke re* 

and lustre of gold, are obtained. The salt is maining in the carbonic acid gas renders its sur- 

readily soluble in water. When heated to a lace visible, which may be thrown into waves 

certain degree, it does not detonate, but fuses, by agitation like water. If a dish of water 

ACID (CARBONIC). This add, bring be immersed in this gas, and briskly agitated, 
a compound of carbon and oxygen, may be it soon becomes impregnated, and obtains the 
fijrmed by burning charcoal ; but as it exista pungent taste of Pyrmont water. In con- 
m great abundance ready formed, it is not ne- sequence of th^ wdght of the carbonic add 
cessary to have recourse to this expedient. All gas, it may be lifted out in a pitcher, or bottle^ 
that is necessary is to pour sulphuric or mu- which, if well corked, may be used to convey 
riatic add, diluted with five or six times ita it to great distances^ or it may be drawn out 
weight of water, on common chalk, winch is a of a vessel by a cock like a liquid. The ef- 
compound of carbonic add and lime. An fects produced by pouring this invisible fluid 
efllbrvescence ensues ; carbonic add is evdved from one vessel to another, have a very sin- 
in the state of gas, and may be received in the gular appearance : if a candle or small animal 
usual maimer. be placed in a deep vessel, the former becomes 

Carbonic add abounds in great quantities extinct, and the hitter expires in a few seconds, 

in nature, and appean to be produced in a afWr the carbonic add gas is poured upon 

variety of drcumstances. It composes V^ of them, though the eye is incapable of disdn- 

tfae wdght of limestone, marble, calcareous gui»hing «ny thing that is poured. If, how- 

spar, and other natural spedmens of calcareous c^""' *» ^ poured into a vessel full of air, in 

earth, from which it may be extricated other **>« aunshme, its density, bdog so much greater 

by the simple application of heat, or by the «h«> **>*' « ^e «>"» renders it slightly visible 

superior affinity of some other add ; most adds by the undulations and streaks it forms in this 

having a stronger action on bases than this. *«»d, as it descends through it. 

Water, under the common pressure of the Carbonic add reddens infusion of litmus; 



ACID 26 CARBONIC. 

iMit the rcdncK Tinisihet by exposure to the air, a spedftc gnmij €it 1.001A. On ftvenag it,' 
M the add fiiet off. It has a peculiar sharp the gas is as eompleteljr expelled as by boiling, 
taste^ which may be perceived over vats in By artificial pressure with fordog puaapa^ 
whidi wine or beer is fermenting, as also in water may be made to abaoib two or three 
sparkling Champaign, and the brisker kinds of times its bulk of carbonic acid. When thape 
dder. It consists, in 100 parts, of oxygen is also added a little potash or sodi^ it b»- 
78.78, the other 87.88 being pure carbon. It conies aerated or cariionated alkaline water ; 
not only destroys life, but the heart and a pleasant beverage^ and a not inactive remedy 
muscles of animals killed by it lose all their in several complaints, particularly dyspepaia* 
initability, so as to be insensible to the stimu- hiccup, and disorders of the kidneys. Alcobol 
fan of galvanism. cond^ises twice its volume of carbonic aci«L 
Cartionic arid is dilated by heat, but not The most beautiful analytical experiment vritfa 
otherwise altered by it It is not acted upon caibonic acid is the combustion of potassium 
by oxygen. Charood absorbs it, but gives it in it, the formation of potash, and the depo- 
out agdn unchanged, at ordinary tempera- sition of chaicoaL Nothing shows the power 
tores; but when this gaseous add is made to of chemicd research in a more favourable 
traverse charcoal ignited in a tube, it is con- light than the extmction of an invisiUa gaa 
verted into carbonic oxide; Phosphorus is from Parian marble or crystalUsed spar, and 
insoluble in carbonic acid gas; but is capable its resolution by such an experiment imttk 
of decomposing it by compound affinity, when oxygen and carbon. - From the proportion* 
assisted by sufficient heat ; and Priestley and above stated, 5 gr. of potassium should -be 
Cruickshank have shown, that iron, sine, and used for 3 cubic inches of gas. If lesa bar 
several other metals, are ci^Mble of produdng employed, the whole gas will not be dacooo- 
the same eflecL posed, but a part will be absorbed by the pot- 
Carbonic add appears from various experi^ ash. From the above quantities S^ths of ». 
ments of logenhouss to be of considerable grain of charcoal will be obtained. If a pov- 
utility in promoting vegetation. It is pro- oeldn tube, containing a cdl of fine iron wirs^ 
bably decomposed by the organs of plants, its be ignited in a furnace, and if cariionic add- 
base furnishing part at least of the carbon that be passed backwards and forwards by mrana 
is so abundant in the vegetable kingdom, and of a full and empty bladder attached to the. 
its oxygen contributing to replenish the at- ends of the tube^ the gas will be converted 
mosphere with that necessary support of life, into cartK>nic oxide, aiid the iron will be. 
which is continually diminished by the res- oxidised. 

piration of aninuils and other causes. Carbonic add gas may be rendered liquid 

The most exact experiments on the neutral by great pressure. Take a strong glass syphon, 

carbonates coucur to prove, that the prime and seal the end of its shorter Ic^. Bymeana 

equivalent of carbonic add is 8.75 ; and that of a long glass iiinnd, nearly fill that leg with 

it consists of one prime of carlion ss 0.75-}- strong sulphuric add: obstruct the bended 

8.0 oxygen. This proportion is most exactly part with a bit of platinum foil, and introduce 

deduced from a comparison of tlie spedfic over this small pieces of carbonate of ammo- 

gravities of carbonic add gas and oxygen ; nia till the tube be nearly filled : now acal 

for it is well ascertuned, that the latter, by its strongly by fusion the open end of the tube ; 

combination with charcoal, and conversion into then make the sulphuric add to run over on. 

the fonner, does not change its volume. Now, the carbonate, and leave the tube inclined in 

100 cubic inches of oxygen wdgh 33.8 gr. and such a position as thai all the add may drain 

lOOcubic inchesof carbonic add 4d.5, showing out of the shorter leg. Great care must mean- 

the wdght of combined charcoal in tliat quan- while be taken of the eyes, for the tube is very 

tity to be 18.7. But the oxide of carbon con- apt to explode. When the dean-drained end. 

tains only half the quantity of oxygen which is afterwards placed in a mixture of ice and 

caibonic add does ; and we hence infer, that salt, carbonic add in the liquid state will 

die oxide of carbon consists of one prime of distil over. 

oxygen united to one of caibon. Hiis a priori Liquefied carbonic add is a limpid, colour- 
judgment is confirmed by the weight 8.75de- less body, extremdy fluid, which floats upon 
duced from the carbonates, as the prime equi- the other contents of the tube^ so that the ha- 
▼alent of carbonic add. Therefore we have zardous process of distillation is hardly nece». 
this proportion :•*- sary, though this goes on rapidly at the diffe- 
if 3^8 represent two primes of oxygen or rence of temperature between 38^ and 0^. 
8 ; 18.7 will represent one of cart)on ; 33.8 : Its refractive power is much less than thatof 
3 : : 18.7 : 0.751, bdng, as above, the prime water. Its vapour exerts a pressure of 36 at- 
equivalent or first combining proportion of mospheres at a temperature of 32^. As this li- 
carbon. I f the spedfic gravity of atmospheric quid acid renuuns in contact with concentrated 
air be called l.OOtX), that of carbonic add will sulphuric add, it may be inferred to be free 
be 1.5877, as above stated. from water. For this most interesting disco- 
We have seen that water absorbs about its viery, and other analogous ones on other gases, 
volume of thu acid gas, and thereby acquires we are indebted to Mr Faraday. Pk, Tr. 18^3. 



ACID 27 CARBONIC. 



Hie cnliooates are chancteriMd by efi«r- tlias salt, we have thus a ready mode of d*^ 

▼cadng with afanost all the adds, eren the tecting its aduHeratioos in genenl ; and as it 

acaticw when they evolve their gaseous add, is often of consequence, in manufactures, t» 

wlacht papBcd into lime, water by a tube^ de- know how much alkali a particular specimen 

prives it of iu taste, and converts it into chalk contains, this may be ascertained by tbe quao- 

•ad pure water. tity of sulpburic add it will saturate. 

2%e CQtbmutU vf baryta was, by Dr With- This salt is deliquescent 
crin^ first found native at Alston Moor in It consists of 6 potash 4- ^75 carbooic 

Ounberland, in 1783. From this drcum- add s= 8.75. 

stance it has been termed Witherite by Wer- The bi-carbonale of potath crystallises, a& 

OCT. See Heavy Sfab. cording to Fourcroy, in square prisms, tbe 

It may be prepared by eiposing a solution apices of which are quadrangular pyramids. 

9i pure baryta to the atmosphere, when it According to Felletier, they are tetraedral 

will be covered with a pellicle of this salt by rhomboidal prisms, with dfedral summits, 

absorbing carbonic add; or carbonic acid may The complete crystal has eight faces, two 

be reedved into this solution, in which it will hexagons, two rectangles, and four rhombs, 

immediately form a copious predpitate ; or a It has an urinous but not caustic taster changes 

idulioo of nitrate or muriate of baryta may the syrup of violets green : boiling water £s- 

be predpiuted by a solution of the carbonate solves five-sixths of its weight, and cold water 

of poUnb, soda or anmionia. The predpitate, one-fourth ; alcohol, even when hot, will not 

in cither of these c as es, bdng well washed, will dissolvemore than l*1200th. Itsspecific gr». 

be fbnod to be very pure carbonate of baryta, vity is 2.012. 

CarlMoate of baryta is soluble only in Bi-carbonate of potash melts with a gentle 

4dM times its weight of cold water, and 2d04r heat, loses its water of crystallisation, amount- 

ef boiliiig water, and this requires a long time; ing to |4n, and gives out one-half of its car- 

bnt water saturated with carbonic add die* i^^ic aod. To obtain the bt-carbonate we 

aohrcs l-830th. It is not altered by exposure Qjugt saturate the common cart>onate with 

to the air, but is decomposed by the applica^ carbonic acid, which is best done by passing 

tiflo of m very violent heat, either in a black, ^he add in the state of gas through a solution 

Jeadcrudble^ or when formed into a paste with of the salt in twice its wdght of water, 
fharenal powder. Sulphuric add, in a con- 'j^ bi-carbonate is usually called super- 

ccntrated state, or diluted with three or four carbonate by the apothecaries. It consists of 

psita of water, does not separate tbe carixmic 2 primes of carbonic addB5.500, 1 of 

add vrithi^Tervescenc^ unless assisted by heat, poush sss 6, and 1 of water s= 1.125, in all 

Huriadc mad does not act upon it likewise, 12.625. 

vnlesB diluted with water, or assisted by heat Carbonait of toda has likewise been long 

And nitric add does not act upon it at all, uo- known, and was distinguished from tbe pre- 

less dihited. It has no sensible taste, yet it ceding by the name of mineral atkaii. In 

it cxtremdy poiionotts. commerce it is usually called bariiia or soda ; 

It is oomposed of 2.75 parts of add, and ;„ which state, however, it always contains a 

a75 of baryta. Its prime equivalent is there- mixture of earthy bodies, and usually com- 

fore the sum of these numbers ss 12.5. xaaa. salt It may be purified by dissolving it 

CarbomaU if otrooHa wss first pointed out fn a small portion of water, filtering the solu- 

as distinct from the preceding spedcs by Dr tion, evaporating at a low heat, and skimming 

Crawford, in 1790. See Hsavy Spab. off the crystals of muriate of soda as they form 

It consists of 0.50 strontia -f- 2.75 carbonic on its surface. When these cease to form, 

addss 0.25. the solution may be suffered to cod, and the 

CarbomaU ^ time exista in great abundance caibonate of soda will crystalUze. 
in nature. It has scarcely any taste ; is in- One form of it is fbund in nature. In 

soluble in pure water, but water saturated Egypt, where it is collected from the surface 

with carbonic add takes up l-1500th, though of the earth, particularly after the desiccation 

as tbe add flies off this is precipitated It of temporary lakes, it has been known from 

suHcrs little or no altention on exposure to time immemorial by the name of nt^rum, na- 

the air. When heated it decrepiUtes, iU f^on, or natrum. A caiixmate of soda ex^ 

water flies off, and lastly its add; but this re- portiNi from Tripoli, which is called Trona 

quires a pretty strong heat By this process f^om the name of the place where it is found, 

it is burned into lime. and analysed by Klaproth, contained of soda 

It is composed of a 50 lime + 2.75caibo- 37 parts, carbonic acid .38, water of crystal- 

oic add =s 6,25 ; or in 100 parts, of 66 lime^ Gzation 22.5, sulphate of soda 2. This does 

and 44 acid. See Calca&bous Spab and ^ot effloresce. 
LoagtoVB. The common carbonate crystallises in rhom- 

CurbonaU tfpato$k was long known by the boidal decaiklrons, formed by two qoadrangu- 

name otvegeiahU alkalL lar pyramids, truncated very near thdr bases. 

As water at the usual tempersture of the Frequently it exhibits only rhomboidal In- 
air dissolves racier more than ito wdght of mine. Its spedfic gravity is 1.3591. Its 



ACID 28 CARBONIC. 

taste is urinous, and slightly acrid, without monly produced by sublimation are little bun- 
being caustic. It changes blue vegetable dies of needles, or very slender prisms, so 
colours to a green. It is soluble in less than arranged as to represent herborisations, fent 
its weight of boiling water, and twice its leaves, or feathers. The taste and smell of 
weight cf cold. It is one of the most efflo- this salt are the same with those of pure am- 
rescent salts known, falling completely to monia, but much weaker. It turns the colour 
powder in no long time. On the application of violets green, and that of turmeric brown, 
of heat it is soon rendered fluid from the great It is soluble in rather more than thrice its 
quantity of its water of crystallization ; but is weight of cold water, and in its own weight 
dried by a continuance of the heat, and then of hot water; but a boiling heat volatilites it. 
melts. It is somewhat more fusible than the When pUre, and thoroughly saturated, it is 
carbonate of potash, promotes the fusion of not perceptibly alterable in the air ; hut when 
earths in a greater decree, and forms a glass it has an excess of ammonia, it softens and 
of better quality. Like tliat, it is very tena- grows moist. It cannot be doubted, however, 
dous of a certain portion of its cariwnic acid, that it is soluble in air ; for if left in an open 
It consists in its dry state of 4 soda -^2,15 vessel, it gradually diminishes in weight, and 
acid == 6.75. its peculiar smell is diffused to a certain dis- 
But the crystals contain 10 prime propor- tance. Heat readily sublimes, but does not 
tions of water. They are composed of 22 decompose it 

aoda -f- 1^3 carbonic acid -}- 62.7 water in It has been prepared by the destructive di»- 

100 parts, or of 1 prime of soda ^4.1 of tillationofanimalsubstances, and some others, 

carb. add =: 2.75, and 10 of water ss 1 1.25, in large iron pots, with a fire increased by de- 

in whole 18. grees to a strong red heat; the aqueous liquor 

• Bi-carbonate of soda may be prepared by that first comes over bdng removed, that the 

saturating the solution of the preceding salt salt might not be dissolved in it Thus we 

with carbonic add gas, and then evaporating had the salt ofhartthom. Here, however, it 

with a very gentle heat to dryness, when a was much contaminated by a fetid animal ml, 

white irregular saline mass is obtained. The ftom which it required to be subsequently 

salt is not crystallixable. Its constituents are purified, and is much better fabricated by 

4 soda -|- ^'^ <^i"^ *<^^^ "f" 1* 125 water ^ mixing one part of muriate of ammonia and 

10.625 ; or in 100 parts, 37.4 soda -|- 52 add two of carbonate of lime, both as dry as poa^ 

-}- 10.6 water. The intermediate native com- sible, and subliming in an earthen retort 
pound, the African trona, consists, according Sir H. Davy has shewn that its component 

to Mr R. Phillips, of 3 primes carix>nic add parts vary, according to the manner of prB» 

-}- 2 soda -|- 4 water; or in 100 parts, 38 paringit The lower the temperature at which 

aoda 4- 40 add -f- 22 water. See the artide it is formed, the greater the proportion of add 

Carbonate. and water. Hius, if formed at the tempera- 

Carbonate of magnesia, in a state of imper- ture of 300°, it contains more than fif^ per 

feet saturation with the add, has been used cent of alkali ; ifat 60°, not more than twenty 

in medidne for some time under the simple per cent 

name of magnesia. It is prepared by pre- There are ind^ two or three definite com- 

dpitation from the sulphate of magnesia by pounds of caibonic add and ammonia. The 

means of carbonate of potash. Two parts oif 1st is the solid subcarbonate of the shops. It 

sulphate of magnesia and one of carbonate of consists of 55 carbonic acid, 30 ammonia, and 

potash, each dissolved in its own wdght of 15 water; or probably of 3 primes caibonie 

boiling water, are filtered and mixed together add, 2 ammonia, and 2 water; in all 14.75 

hot: the sulphate of potash is separated by for its equivalent 2d, M. Gay Lilssac has 

copious washing with water ; and the carbon- shewn, that when 100 volumes of ammoniacal 

ate of magnesia is then left to drain, and afler- gas are mixed with 50 of carbonic add, the 

wards spread thin on paper, and carried to the two gases predpitate in a solid salt, which 

drying stove. When once dried it will be in must consist by wdght of 56} add -^ 43^ 

friable white cakes, or a fine powder. ' alkali, bdng in the ratio of a prime equivalent 

Another mode of preparing it in the great, of each. 3d, When the pungent subcarbo- 

will be found under the article Maon£SIA. nate is exposed in powder to the air, it be- 

The pulverulent cart)onate of magnesia of comes scentless 1^ the evaporation of a definite 

the apothecary has a somewhat uncertain com- portion of its ammonia. It is then a com- 

position as to the proportion of add, earth, pound of about 55 or 56 carbonic add, 21.5 

and water. But there exists in nature a car- ammonia, and 22.5 water. It may be repre- 

bonated magnesia in the true equivalent pro- sented by 2 primes of add, 1 of ammonia, and 

portions of 2.75 add to 2.5 base. See Mao- 2 of water, ss 9.875. Another compound, 

NEsm and Dolomite. it has been supposed, may be prepared by 

Carbonate of ammoma, when very pure, is passing carbonic add through a solution <Mf 

in a crystalline form, but seldom very regular, the subcarbonate till it be saturated. This, 

Its crystals are so small, that it is difficult to however, may be supposed to yield the same 

determine thdr figure. The crystals com- product as the last salt M. Gay Luaaac in. 



ACID 29 CHOLESTERIC. 

fen the m-utnl c&rbonate to consist of equal ACID (CHLORIC). Afler AaD (MiP- 

▼olumes of the two gases, though they will not ftiATic). 

directly combine in these proportionft. This ACID (CHLORIODIC). See Aqd 

would g^Te 1& I to 46.5 ; the Tery proportions ( Hysriodic). 

in the scendess salt. For 46.5: lai : : 55: ACID (CHLOROCARBONIC). See 

21.48L Chlorinb, and Chlobocarbonoos Acm. 

The lint is well known as a stimulant ACID (CHLOROCYANIC). See in 

usually put into smelling-hottles, frequently the sequel of Acid (Hydbocyanic). 

with the addition of some odoriferous oil. ACID (CHOLESTERIC). When we 

Carbtmate afglueifta has been examined by treat with nitric acid the fat matter of the 
Yauquelin, and is, among the salts of that human biliary calculi, which M. Chevreul 
earth, that of which he has most accurately proposed to call Cholesterine, there is formed, 
ascertained the properties. It is in a white, according to MM. Pelletier and Caventou, a 
dull, clotty powder, never dry, but greasy, peculiar acid, which they call the Cholesteric 
and soft to the feel. It is not sweet like the ' To obtain it, they cause the cholesterine to be 
other salts of glucina, but insipid. It is very heated with its weight of concentrated nitric 
light, insoluble in water, perfectly unalterable acid, by which it is speedily attacked and dis- 
hy the air, but very readily decomposed by fire, solved. There is disengaged at the same time 

Vauquelin has found, that carbonate of much oxide of azote ; and the liquor, on cool- 
sirconia may be formed by evaporating mu- ing, and especially on the addition of water, 
liate of Btrconia, redissolving it in water, and lets fall a yellow matter, which is the choles- 
predpitating by the alkaline carbonate. He teric acid impure, or impregnated with nitric 
also addsy that it very readily combines so as acid. It may be purified by repeated wash- 
to form a, triple salt with either of the three ings in boiling water. However, after bav- 
alkaline carbonates. See Salt. ing washed it, it is better to effect its fusion 

ACID (CASEIC). The name given by in the midst of hot water ; to add to it a small 

IVoust to an acid found in cheeses, to which quantity of carbonate of lead ; to let the whole 

he ascribes their flavour. boil for some hours, decanting and renewing 

M. Braconnot shows that the properties the water from time to time ; then to put the 

assigned to caseic acid belong to various sub- remaining dried mass in contact with alcohol, 
stanrps, none of which has any title to be * and to evaporate the alcoholic solution. The 

considered » a peculiar acid. The substances residuum now obtained is the purest possible 

present, according to him, are,— free acetic cholesteric acid. 

add, apo9q>edinef animal matter soluble in This Held has an orange-yellow colour when 

water and insoluble in alcohol ; animal mat^ it is in mass ; but it appean in white needles, 

ler soluble in both ; a yellow acrid fluid oil, (whose form it is difficult to determine), when 

* a brown rcsiD,' acetate and muriate of potash, we dissolve it in alcohol, and leave it to 

and traces of acetate of ammonia. spontaneous evaporation. Its taste is very 

ACID (CETIC). The name given by feeble, slightly styptic, and resembles that 

M. Chevreul to a supposed peculiar principle of butter. Its specific gravity is interme- 

of spermaceti, which he has lately found to diate between that of alcohol and water. It 

be the substance he has called Margarine fuses at 58^ C. and is not decomposed till 

combined with a fatty matter. the temperature be rsised much above that of 

ACID (CEVADIC). By the action of boiling water. It then affords oil, water, car- 
potash on the fat matter of the cevadilla,* there bonic acid, and carburetted hydro^n, but no 
is obtained, in the same way as the delphinic, trace of ammonia. It is very soluble in alco- 
the cevadic acid ; only as this is solid, it must hoi, sulphuric and acetic ether, in the volatile 
be separated from the cevadate of baryta, by pils of lavender, rosemary, turpentine, berga- 
hcating this in a retort with phosphoric acid, mot, &c. It is, on tlie other hand, insoluble 
MM. Pelletier and Caventou discovered it. in the fixed oils of olives, sweet almonds, and 
It is in the form of needles, or crystalline castor oil. It is equally so in tlie vegetable 
concretiona, of a fine white colour. Its odour acids, and almost entirely insoluble in water, 
is analogous to Aat of butyric acid. A heat which takes up merely enough to make it 
of W^ C is suflicient to melt it At a tern- redden litmus. Both in the cold and with 
perature not much higher, it sublimes in crys- heat, nitric add dissolves without altering it. 
talUne needles. It is soluble in water, alco- Concentrated sulphuric add acting on it for a 
boi, ether; and unites to the buses, forming considerable time, only carbonizes it 
salts of little smelL Tlie cevadate of am- It appean tlutt the cholesteric acid is capa^ 
DKHiia gives a white predpitate with the salts ble of uniting with the greater part of the 
of peroxide of iron.— '^nn. de Cftim, et d« saliflable bases. All the resulting salts are 
JHiytm zlv. coloured, some yellow, otben orange, and 

pthen red. The cholesterates of potash, soda, 

• Cevadills, petite oripe, rhordeolum), a plant, ac- ammonia, and probably of morphia, are very 

SnXSTlf iSSSfSX'sSSSr Wu^^ "'"W" "^ deliquacent ; JnK«t .It the od«r. 

mer called CevadiUa Aroericona, wbicb is corrosive. are insoluble, or nearly so. Tliere is none of 



ACID 9) CHROMIC 

tfacm which cannot be dccompooed by ail the —A hot and concentnled solution of the bi- 
minenl adds, except the carbonic, and by the chimnate of potash is to be decomposed by 
greater part of the vegetable acids; so that on fiuosilicic acid; the liquid is to be filtered 
pouring one of these acids into a solution of and e?aponited to dryness ; the add thus 
the cholestetate, the cholesteric add is in- dried is to be dissolved in as small a quantity 
standy separated in flocks. The soluble cho- of water as possible^ and the clear fluid de- 
lesterates form precipitates in all the metallic canted from the deposit of fluosilicate of pot- 
solutions, whose base has the property of Mh which has passed the filter. The separa- 
flmning an insoluble or slightly soluble salt tion of this portion must not be made by a 
with cholesteric acid. filter, for in this state the chromic acid at- 

MM. Pelletier and CaTentou found the cbfr- tacks the paper, and is itself converted into 

lesfeerate of baryta to consist of 100 of add, oxide of chrome. 

and 56. 259 base ; whence the prime equivalent To prepare the fluosilidc add in suffidenk 
of the former appears to be about 17.35. Yet quantity, M. Maus uses a very laige retort 
they observed, on the other hand, that on with a long neck. He puts into it the mix- 
treating the cholesterete of lead with sulphuric ture of fluor-spar and glass, and adds sulphu- 
add, they obtained as much sulphate of lead ric add to about three times the amount of 
as of chdesterate. From this experiment, the the fluor-epar in wdgfat, and mixes the whole 
equivalent of the dry acid would seem to be well. A large globe with a long neck is then 
5 : hence we may imagine^ that when the provided, and a suffident quantity of water 
cholesteric add unites to the oxide of lead, put into it ; the neck of the retort is intro- 
and in general to all the oxides which have a duced, the globe shaken to moisten the inte- 
slight lenity for oxygen, there takes place rior with water, and the fluosilidc gas evohr- 
something similar to what happens in the re« ed by the application ot heat When it 
action of oxide of lead and oxalic add. Jottrn, arrives in the globe it condenses in the water, 
de Pharm. iiL 292, and as soon as the quantity of silica produced 

ACID (CHROMIC). Tins add was at retards the contact of the gas and water, the 
first extracted from the red lead ore of Siberia, globe is again shaken and the operation con- 
by treating this ore with carbonate of potash, tinned. In this way no gas escapes, and the 
And separating the alkali by means of a more water soon becomes saturated with the add ; 
powerful add. In this state it is impure, * the silica is easily separable, 
forming a red or orange-coloured powder, of a Chromic add is soluble in water, and crya* 
peculiar rough metallic taste. If this powder tallises, by cooling and evaporation, in long- 
be exposed to the action of light and heat, it iah prisms of a ruby red. Its taste n acrid 
kses its acidity, and is converted into green and styptic. Its spedfic grarity is not ex- 
oxide of chrome^ giving out pure oxygen gas. actly known ; but it always exceeds that of 

To obtain pure chromic add, we must <&tii water. It powerfully reddens the tincture of 

fluor>spar, cbroroate of lead (the ydlow pig- turnsole. 

ment), and sulphuric add (anhydrous ?) in a Its action on combustible substances is Kttle 

leaden retort, when a gaseous mixture of known. If it be strongly heated with chor- 

diromic and fluoric adds is evolved, that is coal, it gnjfws black, and passes to the metallic 

readily absortMble by water. This mixed gas state without melting, 

affords a thick orange smoke, and on coming Of the adds, the action of the muriatic on 

in contact with air, deposits small red crystals it is the most remarkable. If this be distilled 

of chromic add. Ammoniacal gas introduced with the chromic add, by a gentle heat, it ia 

into this gas, contained in glass jan lined with readily converted into chlorine. It likewise 

resin, bums with explosion. Crystals of chro- imparts to it by mixture the property of dis- 

mic add are also decomposed in ammoniacal solring gold ; in which the chromic resembles 

gas with a flash of light, and become protoxide the nitric acid. This is owing to the weak 

of chromium. Water, by absorbing this adhesion of its oxygen, and it is the only one 

mixed gas, acquires an orange tint ; from of the metallic adds that possesses this pro- 

whicfa, bj evaporation, pure chromic add is perty. 

obtained, the fluoric being volatilised. If the The extraction of chromic add from chrome 

gas be recdved in a deep and moistened pla- ore is also performed by igniting it with its own 

tinum vessel, it descends, saturates the water, wdght of nitre in a crucible. The residue ia 

and is then entirely absori>ed by the fluoric lixiviated with water, which bdng then filtered 

acid, which is at length dissipated, the vessel contains the chromate of potash. On pouriqg 

becoming filled with a red snow, consisting of into this a little nitric add and muriate of 

chromic acid. This crystalline matter, when baryta, an instantaneous predpitate of the 

heated to redness in a platinum dish, fuses, chromate of baryta takes place. AAer having 

explodes with a flash, and resolves itself into procured a certain quantity of this salt, it 

protoxide and oxygen. The crystals obtained must be put in its moist state into a capsule, 

from the water do not present this pheno- and dissolved in the smallest possible quantity 

menon. of weak nitric acid. The baryta is to be 

M. Maus prepares chromic add as folloiifs : th<?n precipitated by very dilute sulphuric 



ACID 



31 



CITRIC. 



aadf ttkiag care not to add an excess of it. 
When the liquid is found bj trial to contain 
DCttbcr fulphuric add nor baryta, it must be 
filtered. It now consists of water, with nitric 
and chromic adds. The whole is to be eva» 
porated to dryness^ conducting the heat at the 
end so aa not to endanger the decompoution 
at the chromic acid, whTch will remain in the 
capsule under the form of a reddish matter. 
It roust be kept in a glass phial well corked. 
Chromic add, heated with a powerful add, 
becomes chromic oxide; while the latter, 
heated with the hydrate of an alkali, becomes 
cfaramic add. As the solution of the oxide 
is green, and that of the add yellow, these 
traBsmutations become Tery remarkable to the 
eye. From Berselius's experiments on the 
combinations of the chromic add with baryta, 
and oxide of lead. Us prime equivalent seems 
to be 6.5 ; consisting of 3,5 chromium, and 
3.0 oxygen. See Chromium. 

It readily unites with alkalis, and is the 
only add that has the tproperty of colouring 
iti salts, whence the name chromic has been 
given it. 

Cbromate of potash is obtained from the 
ferriferous chrome ore, by igniting it with 
nitres as described above. By careful eva- 
poration it may be obtained in crystals, tlie 
usual form of which is four-sided prisms ter- 
minated 1^ dihedral sunnnits, or oblique four- 
|ided prisms, terminated by four-sided pyra- 
mids. Their colour is bright yellow, llidr 
taste is cooling and disagreeable. Water at 
60^ dissolves about half ito wdgbt of this salt, 
and boiHng water much more. It is insoluble 
in akoboL Its spedfic gravity is 2.6. Heat 
causes the ssli to assume a transient red tint, 
wfaidi passes into yellow on cooling. It con« 
tains no water of crystallization. 1 ts constitu- 
ents are chromic add^6.d, potash 6, =s 12.5. 
To test cbromate of potash, add a large ex- 
cels of tartaric add, which decomposes the 
chromic add, and gives the whole the ame- 
thystine hue of tartrate of chromium. If 
the cbromate has been pure^ this liquid will 
afford no predpitate with the nitrates of ba- 
ryta or silver ; whence the absence of muri- 
ste or sulphate of potash may be readily as- 
cotained. Nitre may be detected by the 
fomes of nitric add disengaged by pouring a 
little sulphuric add on the nit. 

Bi-diromate of potash is easily formed, by 
adding to a saturated solution o^ the yellow 
dvomate some dilute nitric add. On heat- 
ing the mixture, the orange precipitate, which 
ensues on the addition of the nitric add, is 
dissolved, and, by slow cooling, fine crystals 
of bi-cfaromate may be obtained, llidr form 
is that of square tables with bevelled edges, or 
flat four-sided prisms. Tbey are permanent 
in the air. Their taste is metallic and bitter. 
Water at 60° dissolves about one>tcnth of 
this salt ; but boiling water dissolves nearly 
half its weight. It is not soluble in alcohol. 



Its sp. gr. is 1.96. It is anhydrous. It. 
consists of chromic add 13, potash 6, s= 19. 

Cbromate of baryta is very little soluble 

Mr Henry Stokes has described three new 
double chromates, obtained by adding cbro- 
mate of potash to sulphate of sine, and slso to 
sulphate of nickel, and to sulphate of copper. 
They all contain very little chromic add, are 
pretty soluble in water, crystallise in tsbles, 
and undergo no cliange in the atmosphere. 
In 100 parts of the sine salt, there are only 
one-third of a part of chromic acid, and not 
two parts in 100 of the nickel salt 

When chromic add is melted with borax, or 
its glass, or add of phosphorus, it communi- 
oates to it a beautiful emerald-green colour. 

If paper be impregnated with it, and ex- 
posed to the sun a few days, it acquires a 
green colour, which remains permanent in the 
dark. 

ACID (CHROMO-SULPHURIC).— 
When cbromate of baryta is treated with di- 
lute sulphuric add in excess, the liquid, on 
being filtered and evaporated, lets fall little 
quadrangular prisms of a deep red colour. 
These crystals, which may also be obtained 
by mingling chromic and sulphuric adds in 
a proper state of concentration, are obrioua- 
ly a compound of the two adds in atomic 
proportions, stated by M. Gay Lussac at 
130a64 chromic add, and 501.16 sulphuric. 
By our numbers, there are thus two atoms 
of the chromic to one of the sulphuric acid. 
This compound acid is deliquescent. When 
the alcoholic solution is highly concentrated 
it explodes, while the chromic add is con* 
veited into the green oxide of chrome, with 
the simultaneous production of a little suU 
phuric ether and sweet oil of wine. 

ACID (CHYAZIC). See AoBs (Hy* 
DBOCYANicand Fbbrocyanic). 

ACID (CITRIC). To procure thisadd, 
boiling lemon-juice is to be saturated with 
powdered chalk, the weight of which is to be 
noted ; and the powder must be stirred up 
from the bottom, or the vessel shaken from 
lime to time. The neutral saline compound 
falls to the bottom, while the mudlage re^ 
mains suspended in the watery fluid, which 
must be decanted off; the remaining preript* 
tate must then be washed with warm water 
undl it comes off clear. To the powder thus 
edulcorated, a quandty of sulphuric add^ 
equal the chalk in wdgbt, and diluted with 
ten parts of water, must be added, and the 
mixture boiled a few minutes. The sulphu- 
ric add combines with the earth, and forms 
sulphate of lime, which is left when the 
cold liquor is filtered, while the disengaged 
add of lemons remains dissolved in the fluid. 
This last must be evaporated to the consist* 
ence of a thin syrup, which yields the pure 
dtric acid in little needle-like crystals. It is 
necessary that the sulphuric add should be 
rather in excess, because the presence of a 



ACID 



32 



CROCONJC. 



small qaantity of lime will prevent the crys- 
tallization. 

To have it perfectly pure, it mutt be re- 
peatedly crystallised ; and thus it forms very 
large and accurately defined crystals in rhom- 
boidal prisms, the sides of Mrhich are inclined 
in angles of 60^ and 120^, terminated at each 
end by tetraedral summitSi which intercept the 
solid angles. 

. Its taste is extremely sharp, so as to appear 
cauitic. It is among the Tegetable adds the 
one which most powerfully resists decompo- 
sition by fire. 

In a dry and warm air it seems to efflo- 
resce ; but it absorbs moisture when the air 
is damp, and at length loses its crystalline 
Ibm. A hundred parts of this add are so- 
luble in seventy-five of water at 60^, accord- 
ing to Vauquelin. 'Diough it is less alter- 
able than most other solutions of v^etable 
acids, it will undergo decomposition when 
long kept 

The crystals of dtric acid, according to 
Berselius, contain 79 per cent of real acid. 
The rest is water. The same chemist found 
IVom dtrate of lead that the prime equivalent 
of the crysuls was 9.5, while that of the real 
add was 7.368; and its constituents were 
oxygen 54L831, carbon 41.369, hydrogen 
3.800. My own experiments on citric acid 
led me to conclude that its prime equivalent 
in the crystalline state was 8.375 ; and that it 
consisted of oxygen 59.7, carbon 35.8, and 
hydrogen 4.5> Two atoms of oxygen and 
two of hydrogen separate when citric acid is 
combined with oxide of lead in what is called 
the dry citrate of this metal. The prime 
equivalent of the acid in this state becomes 
6.125. Dr Prout finds the crystals of dtric 
add to consist of carbon 34^28, water 42.85, 
and oxygen 22.87. Vauquelin found that 
36 parts of crystallized dtric add took for 
saturation 6 1 of bi-carbonate of potash. Hence 
the prime equivalent of such acid is 7.45 ; 
between which, and the number given by Ber- 
selius, mine is nearly the mean. Dr Prout*s 
analysis accords closely with mine ; his total 
oxygen being 60.95, and his hydrogen 4.77. 

If a solution of baryta be added gradually 
to a solution of dtric add, a flocculent preci- 
pitate is formed, soluble by agitation, till the 
whole of the acid is saturated. This salt at 
fknt foils down in powder, and then collects 
in silky tufts, and a kind of very beautiful 
and shining silvery bushes. It requires a 
large quantity of water to dissolve it 

The citrate of lime has been mentioned 
already, in treating of the mode of purifying 
the add. 

. The dtrate of potash is very soluble and 
deliquescent 

The dtrate of soda has a dull saline taste ; 
dissolves in less than twice its wdght of 
water; crystallizes in six-sided prisms with 
flat summits; effloresces slightly, but does not 



fiUl to powder; boils up, swells, and is re- 
duced to a coal on the fire. 

Citrate of ammonia is very soluble; doe« 
not cr]rstallize unless its solution be greatlj 
ooncentrated ; and forms dongated prisms. 

Citrate of magnesia does not ciy^llizei 

Hie dtric add is found in many fruits 
united with the nwlic add; which see, ttM 
'the process of separating them in this case. 

Citric add bdng more costly than tartaric, 
nnay be occasionally adulterated with it This 
fraud is diacoTered, by adding slowly to the 
add dissolved in water a solution of carbonate 
of potash, which will give a white pulverulem 
predpitate of tartar, if the dtric be contami- 
nated with the tartaric add. When one pmri 
of dtric add is dissolved in 19 of water, the 
solution may be used as a substitute for lemon- 
juice. If before solution the crystals be tri- 
turated with a little sugar and a few drops ol 
the oil of lemons, the resemblance to the na- 
tive juice will be complete. It is an antidote 
against sea scurvy; 'but the admixture ol 
mucilage and other v^etable matter in tl^ 
recent fruit of the lemon, has been supposed 
to render it preferable to the pure add of the 
chemist See Salt. 

ACID (COLUMBIC). The experiments 
of Mr Hatchett have proved, that a peculiar 
mineral from Massachusetts, deposited in tbe 
British Museum, consisted of one part of 
oxide of iron, and somewhat more than three 
parts of a white-coloured substance, possessing 
the properties of an add. Its basis was me- 
tallic. Hence he named this ColumbiunHy 
and the add the Columbic. Dr WoUaston, 
by very exact analytical comparisons, prove<^ 
that the acid of Mr Hatchett was the oxide 
of the metal latdy discovered in Sweden, b7 
Mr Ekeberg, in the mineral yttrotantalite^ 
and thence called tantalum. Dr WoUaston** 
method of separating the add from the mU 
neral is peculiarly el^^t One part of tan^ 
talite, five parts of carbonate of potash, and 
two parts of borax, are fused together in * 
platina crudble. The mass, afler bdng sof- 
tened in water, is acted on by muriatic addk 
The iron and manganese dissolve, while thi 
columbic add remains at the bottom. It il 
in the form of a white powder, which is in* 
soluble in nitric and sulphuric acids, but 
tialiy in muriatic. It forms with baryta 
insoluble salt, of which the proportions, ad^ 
cording to Berzelius, are 24.4 add, and 9.7d 
baryta. By oxidizing a portion of the rw 
vived tantalum or columbium, Berxelius com 
dudes the composition of the add to be 101 
metal and 5.485 oxygen. 

ACID(CROCONIC). When potassiui 
is prepared from calcined tartar by Brunm 
method, a gas is evolved which deposits 
greyish-brown substance on cold bodies, 
substance, with a little water, is separated itiN 
to two parts ; one very soluble, yidding I 
brownish-yellow liquid, which, spontaneoualf 




r 



ACID 33 FLUORIC. 

conccp Uated , farniaba an acicular orangfr- a reoeiTer of the aame metal, sunoutided by 
coloured salt This salt, purified by repeated ice. On .applying a moderate beat to the 
cv3rstallixation, has been called by M. Gmelin alembic, the fluoric add will rise in ▼apours, 
erocono/c of potash, because it contains a yel- which will condense in the receiver into an 
lovr add* which yidds many com bi nations of intensely active liquid, first procured by M. 
tbe saoie eolourn Gay Lussac^ and since examined by Sir H. 

CroconaU tf poiash is neutral, inodorous, Davy. 
liBving a weak taste like that of nitre. Its It has the appearance of sulphuric add, 
primitive form is a ibombdd of 106^ and but is much more Tolatfle, and sends off 
74i^. Croconie add is obtained bj treating white fumes when exposed to air. Its spe- 
tfiis aalt with absolute alcohol, to which a dfic gravity is only 1.0609. It must be ex- 
little sulphuric add has been added; sulphate amined with great caution, for when applied 
oT pota^ is fmxaed, and the CROOONic ACQ) to the skin it instantly disorganizes it, and 
is dissolved. It crystallises in grains or nee- produces very painfnl wounds. When pot- 
dlcs ; is transparent, of a fine yellow colour, assium is introduced into it, it acts with in- 
inodoious, of a rough add taste, and reddens tense energy, and produces hydrogen gas and 
litmua. M. Gmelm thinks that this add is a neutral salt : when lime is made to act 
m, hjrdradd like the prussic Hydrocroconic upon it, there is a violent heat exdted, water 
acid <x>nsi8ts of carbon 23,23, hydrogen 0.77, is formed, and the same substance as fluor- 
oxygen 24w81, water 13.98, which in the salt spar is produced. tVith water, in a certain 
of potash are united with 37.21 of that al- proportion, its density increases to L25. 
kalL When it is dropped into ^ate^, a hissing 

ACID (CYANIC). See in the sequel of noise is produced with much heat, and an 
Acm (HYDfiOCYANic). add tfuid, not disagreeable to the taste. Is 

ACID (DELPHINIC). Tbe name formed, if the water be in sufiSdent quantity. 
^▼en by M. Chevreul to a substance which It instantly corrodes and dissohes glass. 
he has extracted fVom the oQ of the dolphin. In ordo* to insure tbe absolute purity of 
It resembles a volatile oil ; has a light lemon the add, tbe first portions that come over 
colour, and a strong aromatic odour, analo- may be set apart, as possibly containing some 
l^ous to that of randd butter. Its taste is silicated fluoric add, if any silica was present 
pungent, and its vapour has a sweetened taste in the spar. 

of eSier. Its density at 14^ C. is 0.941. It Considerable difibrence of opnion prevails 
is slightly soluble in water, and veiy soluble concerning the prime equivalent of this add, 
in akohoL Tlie latter solution strongly red- as it exists in its dry combinations. Sir H. 
dens litmus. 100 parts of delphinic add Davy states, that 100 fluor-spar yield 175.2 
neotraliae a quantity of base which contains sulphate of lime ; whence we deduce the 
9 of oxygen, whence its prime equivalent primeeqUivalentof fluoric acid to be }»35,io 
t mppesn tobe WAl.'^^^nnalet de Chim. et de lime 3^5, and oxygen l.OO. Benelius, in 
^ky*, viL bis last series of experiments, gives from 

ACID (ELLAGIC). Tbe deposit which fluate of lime 1.357, for the equivalent of 
forms in Infusion of nut-galls left to itself, is fluoric add. 

not composed soldy of gallic add and a mat- Of all the tf uatcs whid) he analyzed, that 
ter which colours it ; it contain^ besides, a of lime was the only one which he succeeded 
i little gallate and sulphate of lime, and a new in fredng perfectly Irom the last portions of 
t add, which was pointed out for the first time silica; and hence he regards the above re- 
f. by M. Chevreul in 1815— an add on which suit as quite satisfactory. In three experi- 
i M. Braconnot made observations in 1818, ments, in which he saturated carbonate of 
K and which he proposed to call add ellagic, lime with pure fluoric add, evaporated to 
is liom the word galle reversed. Probably this dryness and ignited, be obtained from 100 
V add does not exist ready formed in nut>galls. parts of such fluate, on decomposing it by 
It is insoluble; and, carrying down with it sulphuric add, l74i.9, I75» and 175^12, <^ 
19 the greater part of the gallic add, forms the ignited sulphate of lime«<— ^nno/lef de Chim» 
c. yellowish crystalline deposit. But boilii^ ei de Pkyt, 1824. This accordance between 
15 water removes the gaHic add from the ella- Sir £[. Davy's result with the native fluate^ 
f. gic ; whence the means of separating- them and that of Bersdius ^th the artificial, 
i. from one aDOthcr.^^nn. de Chim. el de Phys. seems decisive. 

)0 ix. 181. Berzeliu's observes, that fluate of lime can 

ACIDS (FERROCYANIC and FER- be prepared only by saturatmg tbe recently 
, RURETTED CHYAZIC). See in the predpitated moist carbonate with pure fluoric 
^5 sequel of AcQ) (Htdbocyanic). add. The fluate is thus obtained as grano* 

s ACID (FLUORIC). Tbe powder of lar as the carbonate, and may be washed; 

is ciystallixed fluor-apar is to be put into a silver whereas, if prepared by double decomposi- 
n. I or leaden alembic, and its own wdght of sul- lion, we obtain a jelly which dois not change 
a pburic add poured over it Adi4>t to the even by eva^ration, and whidi cannot be 
ly I alembic a silver or leaden tube terminating in washed* 

• C 



ACID Si FLUORIC. 

Dr HMmiMm, in Us dabonte work on the liquid fluoric add. ** In this case, gas 
the fint principles of Chemistry, assigns 1.25 appeared to be produced from bodi tbe ne- 
as the prime equivalent of fluoric add. He gattre and positive surftces; but it was pro- 
deduced this number from the quantity of bably only the undecompounded acid, reo- 
chloride of calcium, and of chloride of b»- dered gaseous, which was evdved at tbe posi- 
'rium, to which a certain weight of fluate of tive surface ; for during tbe operation the 
soda was found to be equivaleot in the way fluid became very hot, and speedily diminisb- 
of double decomposition. But his fluate of ed."-— « In the course of these investigationa 
soda was prepared in a very questionable I made sereral attempts to detadi hydrogen 
manner ;--by adding carbonate of soda in from tbe liquid fluoric add, by tbe agency of 
small quantities to a solution of carix>nate of oxygen and chlorine. It was not decomposed 
ammonia, previously saturated with sih'rated when passed through a platina tube heated 
fluoric gas ; evaporating the whole to dry- red-hot with chlorine^ nor by bdng distillwi 
ness ; redissolving and evaporating till the from salts containing abundance of oxygen* 
fluate of soda crystallized in transparent or those containing abundance of chlorine.** 
crusts. - As a fiuosilicate of ammonia exists, The marvellous activity of fluoric add may 
possibly some of this may have been formed, be inferred from the following temarks oif 
of which some silica mi^t remain associated Sir H. Davy^ from which also may be esti- 
witb hb soda. Nor does his fluate of soda mated in some measure, the prodigious diffi- 
correspond in character to the description of -culty attending refined investigations on this 
this salt directly formed by Berzelius, by sa- extnordinary substance, 
turating carbonate of soda with pure fluoric <* I undertook the experiment of dectris- 
add. By spontaneous evaporation, fluate of ing pure liquid fluoric add with considerable 
soda is, obtuned in transparent cubes, or re- interest, as it seemed to offer the most prob»- 
'gular octahedrons; by heat, in groups of ble method of ascertaining its real nature; 
small cubical grains. It contains no water but considerable difficulties occurred in exe- 
of crystallization, and is more difllcult of cuting the process. The liquid fluoric add 
funon by heat than glass. At the tempera- immediately destroys glass, and all animal 
ture of 60^ F. 100 parts of water dissolve and vegetable substances; it acts on all 
only 4fi.8 parts of it ; and at the bdliog point bodies contdning metallic oxides ; and I 
only 4fi.3. Dr Thomson says, that he dis- know of no substances which are not rapidly 
solved 5,25 grains of his sdt (white crusts, dissolved or decomposed by it, except metals, 
freed bv ignition from thdr water of cryttaU charcoal^ phosphorus, sulphur, and certain 
UstatUm^ in a lUiU water. From the mode of combinations of chlorine. I attempted to 
preparing his primary salt, from its appear- make tubes of sulphur, of muriates of lead, 
ance, and from the defect in the process of and of copper containing metallic wires, by 
double decomposition for forming pure fluate which it might be dectrtzed, but without suc- 
of lime^ Dr Thomson's atomic number seems cess. I succeeded, however, in boring a piece 
entitled to little confidence. of horn silver, in such a manner that I was 

Fluoric add may dther be regarded as a able to cement a platina wire into it by means 

compound of oxygen with an unknown base of a spirit lamp ; and by inverting this in a 

to be called fluor; or of hydrogen with an tray of platina, filled with liquid fluoric add, 

electro-negative element to be called fluorine. I contrived to submit the fluid to the agency 

If fluor-spar consist of lime associated vdth of dectridty in such a manner, that, in suc- 

an oxygen add, then this will contdn one cessive experiments, it was possible to collect 

prime proportion of oxygen =s 1, combined any elastic fluid that might be produced, 

with one prime of fluor = 0.357. Were Opersling in this way with a very weak voU 

this latter number 0.375, to which it ap- taic power, and keeping the apparatus cool 

preaches, it would equal the wdght of three by a freezing mixture, I ascertained that the 

atoms of hydrogen. But if fluor-spar be platina wire at tbe positive pole ra^dly cor* 

truly a fluoride of caldum, then, from its roded, and became covered with a chocolate 

prime equivalent 4.857, we deduct the prime powder ; gaseous matter separated at the ne- 

equivalent of caldum 2.5, and the remainder gative pole, which I could never obtain in 

2.357 will be the prime of fluorine, a number suflSdentquantities to analyze witii accuracy, 

nearly 19 times that of hydrogen. but it inflamed like bydnq^en. No other in- 

From the remarkable property possessed by flammable matter vras produced when the 

fluoric add of dissolving silica, it bas been add was pure.** M. Kuhlmann transmitted 

employed for etching on glass, both in the anhydrous sulphuric add in vapour, over 

gaseous state and combined with water. The ignited fluor-spar contdned in a platinum 

glass is previously coated with white bees* tube^ but no change ensued. Hie add was 

wax ; on which the figures are traced with a recondensed in part in the farthest tube^ and 

sharp point no trace of fluoric add vras perceptible. 

With the view of separating its hydrogen, But when a little water was added to the 

Sir H. Davy applied the power of the great sulphuric add, the fluoric was instantly dis- 

▼oltdc batteries of the Royal Institution to engaged from the spar. 



ACID 



36 



FLU08ILICIC. 



Hm MDii^ cbcmiit deedinpoaed flvor^lpar 
by tmMDBitting dry muriatic add gas orer it 
%iiited in a tubch Chloride of lime remaiiw 
ed in the tabe^ and pure hydrofluoric gas 
came over. 100 parts of the fluoride of 
caldum (fluor-spar), thus treated, became 
143.417 parts of chloride of caldum, con- 
aistii^ of 52.819 parts of caldum, (present 
in 100 of fluor-qiar), united to 90.596 of 
chlorine). Bot this latter quantity must 
have Uberated 2.511 parts of hydrogen, says 
2C Kuhlmannr which must therefore have 
oomhined with the 47.181 parts of fluorine 
in the vpmr, to form 4^692 parts of hydro- 
fluoric add. This must consist then of 
94b 941 parts of fluorine, and 5.059 hydro- 
gen, in 100. 

The salts fbrmed by fluoric add and ae- 
Tend bases, have been lately examined by M. 
Bendius with his accustoined precision. 

SMpeifluaU of poiaah* Tliis add fluate is 
obtained by mixing with the add a quantity of 
potash, insuflident to saturate it. On con* 
centrating the solution, a little of the redun- 
dant acid flies off; but the greater part re- 
mains and crystallises with the alkali. This 
salt, when hotted, fuses, and leaves 74.9 per 
cent of nentnd fluate^ while fumes of fluoric 
add are. voladfised. Bendius regards the 
above add salt as composed of an atom of 
fluate of potash, and an atom of hydiated 
fluoric add* 

FluaU ofpolaah is prepared by saturating, 
imperfectly, fluoric acid with cari>onate of 
poissh, eviqiomting and heating so as to expd 
the exccu of add. It has a sharp saline 
taste^ b very alkaline, and deliquesces in the 
air. It crystailizes very difficultly in water, 
and then forms cubes or rectangular prisms, 
with stair-like scales, similar to common salt 
AeidJlwMU ofModa. This salt is little so- 
iuUe in cold water. By a slow spontaneous 
evaporalioo it affords rhomboidal crystals, 
having a sharp taste, and distinctly add. 
Heat separates the fluoric add in a concen- 
trated state, without changing the form of 
the crystals, and 68il per cent of neutral 
fluate remain. Berzelius considers this salt 
to be a compound of an atom of fluate of 
aoda, and an atom of hydrated fluoric add. 

Neutral JluaU of ioda, Hiis salt may be 
obtained directly from fluoric acid and car* 
bonate of soda, or by decomposing 100 parts 
of the double fluate of soda and silica, by 1 12 
parti of dried carbonate of soda. When the 
salt is pure, and left to spontaneous evapora- 
tion, it affords transparent cubes of regular 
octahedrons, which often present a pearly 
lustre. Octahedrons are always obtained 
when the solution contains some carbonate 
of soda, but on the contrary, groups of small 
cubic grains when the evaporation is pro- 
duced by elevation of temperature. The 
fluates of potash and soda are isomorphous 
with the muriates of the same bnses^ Fluate 



of soda mehs with more diflicolty than glass. 
100 parts of water at 60° F. dissolve 4.8 of 
it ; and at the boiling point only 4i3. 

Acidjluate of ammonia forms small gra- 
nular crystals, which deliquesce. 

Neutral fluate ofammoma is more volatile 
than sal ammoniac. It is easily obtained by 
heating one part of dry sal ammoniac with a 
little more than two parts of fluate of soda, 
in a crudble of platinum with its lid turned 
upwards. Into this lid a little cold water is 
put, while the bottom of the crudble is heat- 
ed with a spirit of wine lamp. The fluate of 
ammonia thus sublimes perfectly pure in a 
mass of small prismatic crystals. It fuses be- 
fore subliming, and acts on glass even in its 
dry stat^ and at ordinary temperatures. 

The earthy fluates are best prepared by 
digesting their recently precipitated moist 
ca^rbonates in an excess of fluoric sdd. That 
of baryta is slightly soluble in water, and 
readily in muriatic add. 

ACID (FLUOSILICIC). If instead of 
bdng distilled in metallic vessels, the mixture 
of fluor-spar and' oil of vitriol be distilled in 
glass vessels, little of the corrosive liquid will 
be obtained ; but the glass will be acted upon, 
and a peculiar gaseous substance will be pro- 
duced, which must be collected over mercury. 
The best mode of procuring this gaseous body 
is to mix the fluor-spar wi& pounded glass or 
quartz ; and in this case, the glass retort may 
be preserved from corrosion, and the gas ol>- 
tained in greater quantities. This gas, which 
is called silicated fluoric gas, is possessed of 
very extraordinary properties. 

It is very heavy ; 100 cubic inches of it 
wdgh 110.77 gr. ; and hence its sp. gr. is to 
that of air as 3.G32 is to I.OOO. It is about 
48 times denser than hydrogen. When 
brought into contact with water, it instantly 
deposits a white gelatinous substance, which 
is hydrate of silica ; it produces white fiimes 
when suffered to pass into the atmosphere. It 
is not affected by any of the common com- 
bustible bodies; but when potassium is 
strongly heated in it, it takes Are and bums 
with a deep red light ; the gas is absorbed, and 
a fawn-coloured substance is formed, which 
yields alkali to water with slight effervescence, 
and contains a combustible body. The wash- 
ings afford potash, and a salt, from which the 
strong add fluid previously described may be 
separated by sulphuric add. 

The gas formed by the action of liquid 
sulphuric add on a mixture containing silica 
and fluor-spar, the silicated fluoric gas or fluo- 
silicic add, may be regarded as a compound 
of fluoric add and silica. It affords, when 
decomposed by solution of ammonia, 6 1.4 per 
cent of silica ; and hence was at first sup- 
posed by Sir H. Davy to consist of two prime 
proportions of add = 2.652, and one of silica 
s= 4.066, the sum of which numbers might 
represent its equivalent ss 6.718. One 



ACID 



36 



FLUOBORia 



▼olurne of it condenses two Tolumes.of am- 
monia, and they form together a peculiar 
saline subiitance, which is decomposed by 
water. The composition of this salt is easily 
reconciled to the numbers given as represent- 
ing silica and fluoric acid, on the supposition 
that it contains one prime of ammonia to one 
of the fluosilicic gas ; for 200 cubic inches of 
ammonia weigh 36.2 gr. and 100 of the add 
gas 1 10.77. Now 36.2 : 2.125 : ; 110.77 : 
6.502i. 

Dr John Davy obtained, by exposing that 

gas to the action of water, thstjV o£its weight 
of silica ; and from the action of water of 
ammonia he separated i^sV ^^ ^^ weight. 
Hence 100 cubic inches consist by weight of 
68 silica and 42 of unknown fluoric matter, 
the gas which holds the silica in solution. Sir 
H. Davy, however, latterly, conceives that 
this gas is a compound of the bases of silica, 
or silicon, with fluorine the supposed basis of 
fluoric acid. 

Berzelius, in his late elaborate researches on 
the fluoric combinations, (^jlnnalet de Cfdm, 
et de Phys> xxvii. 289.), says that the silicated 
fluoric acid should be regarded as nothing else 
than fluate of silica, for it is only with the 
neutral fluates that it can unite without suf* 
fering decomposition ; and that when a portion 
of silica has been separated from it, it can be 
replaced only by an alkali, an oxide, or water. 
When he put silicated fluoric gas in contact 
with carbonate of potash or soda, reduced to a 
very fine powder, there was no more of it ab- 
sorbed than what mi^t be ascribed to mois- 
ture contained in the carbonate ; and the salt, 
after exposure to the gas for several days, had 
absorbed but an extremely small portion of it 
Tlie same result is observed with pure lime 
and the bicarbonate of potash. But the gas 
is very easily absorbed when exposed, even 
irithout moisture, to a finely pulverized fluate, 
dther with an alkaline, earthy, or metallic 
base. At the end of a few hours, the fluate 
is completely saturated with the gas ; showing 
that the portion of fluoric acid and silica ab- 
sorbed, has no need of any new base for its 
saturation. Tliis simple fact shows that the 
pretended fluosilicates, instead of being com- 
binations of a fluate with a silicate, are 
rather combinations of fluate of silica with 
fluates of the other bases. M. Berzelius 
infers from his experiments, that fluate of 
Silica is formed of lOQ parts fluoric acid, 
and 1445 silica. Water separates one-third 
of this silica. 

ACID (FLUOBORIC). If, instead of 
glass or dlica, the fluor-spar be mixed with dry 
vitreous boracic acid, and distiDed in a glass 
vessel with sulphuric acid, the proportions be- 
ing one part boracfc acid, two fluor-spar, and 
twelve oil of vitriol^ the gaseous substance 
formed is of a different kind, and is called the 
fluQboric gas. 100 cubic inches of it weigh 
73.5 gr. according to Sir H. Davy, which 



makee its density be to that off air as 2.41 is 
to 1.00 ; but Dr John Davy states its density 
to that of air as 2.371 to 1.000. It is 
colouriess; its smell is pungent, and resem- 
bles that of muriatic acid; it cannot be 
breathed without suffocation ; it extinguishes 
combustion ; and reddens strongly the tincture 
of turnsole. It has no manner of action on 
glass, but a very powerful one on vegetable 
and annual matter : it attacks them with as 
much force as concentrated sulphuric add» 
and appears to operate on these bodies by 
the production of water ; for whik it carbo- 
nizes them, or evolves carbon, they may bo 
touched without any risk of burning. Ex- 
posed to a bigb temperature, it is not decom- 
posed; it is condensed by cold without 
changing its form. When it is put in contact 
with oxygen, or air, either at a high or low 
temperature, it experiences no change, except 
seising, at ordinary temperatures, the moisture 
which these gases contain. It becomes in 
consequence a liquid which emits extremely 
dense vapours. It operates in the same way 
with aU the gases which contain hygrometric 
water. However little they may contain, it 
occasions in them very perceptible vapours. 
It vaaey hence be employed with advantage to 
show whether or not a gas contBin» moisture. 

No combustible body, simple or compoondy 
attacks fluoboric gas, if we except the alkaline 
metals. Potassium and. sodium, with the aid 
of heat, bum in this gas almost as brilliantly 
as in oxygen. Boron aitd fluate of potash 
are the products of this decomposition. It 
might hence be inferred, that the metal seizes 
the oxygen of the boracic add, sets the boron 
at liberty, and is itself oxidized and com- 
bined with the fluoric acid. According to 
Sir H. Davy's views, the fluoboric gas being 
a compound of fluorine and boron, the pot- 
assium unites to the former, giving rise to 
the fluoride of potassium, while the boron re- 
mains disengaged. 

Fluoboric gas is very soluble in water. Dr 
John Davy says, water can combine with 700 
times its ovm volume, or twice its wei^t at 
the ordinary temperature and pressure of the 
air. Hie liquid has a specific gravity of 
1.770. If a bottle containing this gas be 
uncorked under water, the liquid will rush in 
and fill it with explosive violence. Water 
saturated with this gas is limpid, fuming, and 
very caustic. By heat about one-fifth of the 
absorbed gas may be expelled; but it is im- 
possible to abstract more. It then resembles 
concentrated sulphuric add, and boils at a 
temperature considerably above 212^. It 
afterwards condenses altogether, in strut, al- 
though it contains still a very large quantity 
of gas. It unites with the bases, forming 
salts called fluobontes, none of which has 
been applied to any use. The most impor- 
tant will be stated under the artide Salt. 

The 2d part of the FbiL Transactions for 



ACID 



37 



FULMINIC. 



181Sy cmtains an ezodlent paper by Dr John 
2)bv7 on fiuoailicic and fluoboric gases, and 
tiieeombinations of tbe latter with aramoniacal 
^aa. When united in equal volumes, a pul- 
verulent salt is fonned ; a second volume of 
ammonia, however, gives a liquid compound ; 
and a third of ammonia, which is tbe limit of 
combination, a£fords still a liquid; both of 
them curious on many accounts. " Hiey 
are^" says he, ** the first salts that have been 
observed liquid at the common temperature 
of the atmosphere. And they are additionai 
Acts in support of the doctrine of definite 
p to po r ti ons, and of the relation of volumes.*' 
ACID <FLUOTANTALIC). This 
add is prepared in a similar way to the fol- 
lowing ; and forms, with the bases, salts caH- 
UAjluoimUalatts, 

ACID (FLUOTITANIC). When fluo- 
ric acid is poured on titanic add, the latter 
becomes wann, even after having been previ- 
ously ignited, and dissolves completely with 
<fae aid of heat. Evaporated at a gende heat 
to the consistence of syrup, the solution af- 
Ibrds crystals, which do not redtssolve com- 
pletely in water, but which are decomposed 
into two pecub'ar combinations, of which one 
is addulous and soluble, and the other with 
«scess of base is insoluble. The solution of 
tbe Ibnner, namely of the fluotitanic add, in 
water, is snalc^us to the liquid fluosilidc 
add ; it contains fluotitanic add, and fluoric 
add combined with water. Hie water may 
be replaced by other bases, and in this way 
may be formed a series of salts which M. Ber- 
aeUus calls fiwotitanateu The fiuotitanate 
of potash crystallizes in brilliant scales like 
boradc add, which redissolve in water with- 
out deoompontion. It consists in 100 parts 
4if potash 38.7, titanic add 35^ and fluoric 
add 26.3. 

ACID (FORMIC). To procure pure 
formic add, Gehlen saturates the expressed 
liquor of ants with subcarbooate of potash, 
pours into the compound sulphated peroxide 
of iron, filters, evaporates to the consistence 
of syrup, and distils in a glass retort, with a 
sufficient quantity of sulphuric add. The 
product which passes into the recdver is very 
sour, and without any perceptible odour of 
sulphnrous add. He then puts it in contact 
with carbonate of copper, evaporates the so- 
hitioo, and procures fine blue crystals, which 
he considers as formiate of copp^. Ftook 
this he extracts the pure and the most con- 
centrated add possible, by decomposing the 
salt with two-thirds of its wdght of sulphuric 
add, aided by heat, distilling it into a re- 
cdver, and rectifying by a second distillation. 
From thirteen ounces of formiate thus treated, 
he obtained more than six ounces and a half 
of pure formic add. 

This add has a very sour taste, and con- 
tinues liquid even at very low temperatures. 
ItB^edfic gravity is 1.1 168 at 68°, which is 



much denser than acetic add ever is. Berse^ 
lius finds, tiiat the formiate of lead consists of 
, 4.696 add, and 14 oxide of lead ; and that 
the ultimate constituents of the dry acid are 
hydrogen 2.84 4- carbon 32.40 4- oxygen 
64.76 =100. 

M. Doberdner has recently succeeded 
(See Gilbert's Annales, xi. 107.) in forming 
this add artificially. When a mixture of tar- 
taric add, or of cream of tartar, black oxide 
of manganese, and water, is heated, a tumul- 
tuous action ensues, carbonic add is evolved, 
and a liquid add distils over, which, on su- 
perfidal examination, was mistaken for acetic 
add, but which now proves to be formic acid. 
This add, mixed with concentrated sulphuric 
add, is at common temperatures converted 
into water and carbonic oxide ; nitrate of sil- 
ver or of mercury converts it, when gently 
heated, into carbonic add, the oxides bdng 
at the same time reduced to the metallic 
state. With baryta, oxide of lead, and oxide 
of copper, it produces compounds having all 
the properties of tbe genuine formiates of 
these metals. If a portion of sulphuric add 
be employed in the above process, tbe tartaric 
add is resolved entirely into carbonic add, 
water, and formic add ; and the product of 
the latter is much increased. The best pro- 
portions are, two parts tartaric acid, five per- 
oxide of manganese, and five sulphuric add 
diluted with about twice its wdght of water. 
M. Doberdner finds, that when formic 
add is decomposed by sulphuric acid, it is 
resolved into 24.3 water, and 75.7 carbonic 
oxide, in 100 parts ; or of one volume of 
vapour of water, and two volumes carbonic 
oxide gas ; or two atoms carbon, three oxy- 
gen, and one hydrogen. 

ACID (FULMINIC). Put 6.5 parts 
of nitric add, sp. gravity 1.36 or 1.38, into 
a pint matras, and a piece of coin contain- 
ing nearly 35 parts of pure silver. Pour 
the resulting solution into about 927 parts 
of strong alcohol, and beat to ebullition. 
On the appearance of turbidness, remove 
from the fire, and add by degrees an equal 
quantity of alcohol to the solution, in order to 
moderate the ebullition, and to cool it. Hl- 
ter it when cold, and wash away the whole 
free add. The fulminate of silver is now pure 
and white as snow. Dry it in a steam heat 
for two or tliree hours, after which it will be 
found to equal in wdght the silver employed. 
A slight blow between bard bodies explodes 
it. It may be analyzed by rubbing it with 
the finger with forty times its weight of per- 
oxide of copper, and igniting the mixture in 
a glass tube. 100 parts of it, analyzed in 
this way, afiforded 77.528 of oxide of silver. 
The add associated with this oxide is the cy- 
anic. Hence the ultimate constituents are^ 
in 100 parts, silver 72.187, oxygen 5.341, 
cyanogen 17.16, oxygen (comlnned with the 
silver) 5.312. It consists, therefi^re, of one 



ACID 36 G^I^LIC. 

atom oxide of sUfer, 14^75 ; 8 atam^ cyaixv the retort Thia pipceas fisqpUM gnat care^ 
gen, 6.6; 2 oxygen, 2 ss 2^25. as, if the heat be carried so far as to diaen- 

To prepare alkaline fulminates, chlorides gage the oil, the crystals will be dissolved 
should be used. Thus, to obtain the double immediately. The crystab thus obtained are 
fubninate of silver and potash, decompose pretty large» laminated, and brilliant, 
the fulminate of silver by chloride of potas* M. Baruel, of the School of Medicine at 
aium ; being careful to add no more of the Paris, finds that be can obtain pure gallic 
chloride than is sufficient to precipitate ra- acid by pouring solution of white of egg 
ther less than half the sOver. The solution into the infusion of nut-galls, till this ceases 
will contain the double fulminate. lAebeg and to be disturbed ; then to evaporate the chui- 
Croy Lussac, Afou de CKiim. ei Fhyt. xxv. 286. fied liquid to. dryness, to heat the residuum 
ACID (FUNGIC). The expressed juice with alcohol, to filter the new liquid, and 
of the boletus juglanditf bokiut psetuUhignich' concentrate it to the proper degree for the 
rtiM, the phallus impudicust mertUius cantha" formation of gallic acid. 
reituSf or the pexmt nigra, being boiled to Gallic add placed on a red-hot iron burns 
ooagulate the albumen, then filtered, evapo- witli fiame, and emits an aromatic smell, not 
xated to the consistence of an extract, and unlike that of benzoic acid. It is soluble in 
acted on by pure alcohol, leaves a substance twenty parts of cold water, and in three parts 
which has been called by Braconnotyii/^gic at a boiling heat It is more soluble in alco- 
acid. He dissolved that residue in water, hoi, which takes up an equal weight if heated^ 
added solution of acetate of lead, whence re- and one-fourth of its weight cold. 
mlbed /ungate of lead, which he decomposed It has an acido-astringent taste^ and red^ 
at a gentle heat by dilute sulphuric acid, dens tincture of litmus. It does not attract 
The evolved fungic acid being saturated with humidity from the air. 
ammonia, yielded a crystallized fungate of From the gallate of lead, Benelius infers 
ammonia, which he purified by repeated so- the equivalent of this acid to be 8.00. Its 
lution and crystallization. From this salt, by ultimate constituents are, hydrogen 5.00 -^ 
acetate of lead, and thereafter sulphuric acid, carbon 56.64 -f* oxygen 38.36 ss 100. 
as above detailed, he procured the pure fungic This acid, in its combinations with the Sfr- 
add. lifiable bases, presents some remariLable phe- 

It is a colourless, uncrystallizable, and de- nomena. If we pour its aqueous solution by 
liquescent mass, of a very sour taste. The slow degrees into lime, baryta, or strontia 
fungates of potash and soda are uncrystalliz- water, tliere will first be fonned a greenish- 
able ; that of ammonia forms regular six^ white predpitate. As the quantity of add is 
sided prisms; that of lime is moderately so- increased, the precipitate changes to a violet 
luble, and is not affected by the air ; that of hue^ and eventually disappears. The liquid 
baryta is soluble in fifteen times its wdght has then acquired a reddish tint. Among 
of water, and crystallizes with difficulty ; that the salts, those only of black oxide and red 
of magnesia appears in soluble granular crys- oxide of iron are decomposed by the pure 
tals.. This add precipitates from the acetate gallic acid. It forms a blue predpitate with 
of lead a white flocculent fungate, which is tlie first, and a brown with the second. But 
soluble in distilled vin^^r. When insulated, when this acid is united with tannin, it de- 
it does not affect solution of nitrate of silver ; composes almost all the salts of the perma- 
but the fungates decompose this salt nent metals. 

ACID (GALLIC). This add is found Concentrated sulphuric acid decomposes 
in different vegetable substances which possess and carbonizes it ; and the nitric add con- 
astringent properties, but most abundantly verts it into malic and oxalic adds, 
in the excrescences termed galls or nut-galls. United with baryta, strontia, lime, and 
whence it derives its name. It may be ob- magnesia, it forms salts of a dull yellow co- 
tained by macerating galls in water, filtering, lour, which are little soluble, but more so if 
and suffering the liquor to stand exposed to thdr base be in excess. With alkalis it forms 
the air. It will grow mouldy, be covered salts that are not very soluble in general, 
with a thick glutinous pellicle,, abundance of Its most distinguishing characteristic is its 
glutinous flocks will fall down, and, in the great affinity for metallic oxides, so as, when 
course of two or three months, the sides of combined with tannin, to take tiiem from 
the vessel will appear covered with small powerful acids. The more readily the me- 
yellowisb oystals, abundance of which will tallic oxides part with tlidr oxygen, the more 
likewise be found on the under surface of they are alterable by the gallic acid. To a 
the supernatant pellide. Iliese crystals may solution of gold it imparts a green hue ; and 
be purified by solution in alcohol, and evapo- a brown precipitate is farmed, which readily 
ration to dryness. passes to the metalh'c atate, and covers the 

M. Deyeux recommends to put the pow- solution with a shining golden pelh'cle. With 
dered galls into a glass retort, and apply nitric solution of silver, it produces a similar 
heat slowly and cautiously ; when the acid effect. Mercury it predpitates of an orange- 
will rise and be condensed in the neck of yellow; copper, bcown; bismuth, of a lemon 



ACID 39 HYDRIODIC. 

coloiir; lead, i^te; iioiiy black. Flatina, wfaleh oombloe in aqual volumefly without 

linc^ tin, oobalt, and mangimffte, are not pro- ■ change of their primitive bulk. Its compo> 

dpitated bj it. sition by weight is therefore 8^61 of iodine 

On diaeahring gallic add in ammonia, and -f- 0.0694 hydrogen, which is the relation 

phdng the solution in contact with oxygen, of thdr gasiform densities; and if 8.61 be 

3L Doberdner found that it absorbed suffi- divided by 0.0694» it will give the prime of 

cicnt to convert all the hydrogen of the gallic iodine 124 times greater than hydrogen ; 

add into water. In this way the acid is con- and as the prime of oxygen is eight times 

▼erted into uhnm, which is composed of 2 more than that of hydrogen, on dividing 
atoms carbon 4- 1 hydrogen -f- 2 oxygen. 124 by 8, we have 15.6 for the prime equi- 

100 parts of gallic acid absorb 38 of oxygen, valent of iodine ; to which if we add 0. 125^ 

within twenty-four hours. Thesohitionmean- the sum 15.625 represents the equivalent of 

while becomes brown-coloured and opaque. hydriodic add. The number deduced for 

GalUc add is of extensive use in the art of iodine, from the relation of iodine to hydro- 

dyeing, aa it constitutes one of the prindpal gen in volume, approaches very nearly to 

ii^rediente in all the shades of black, and is 15.621, which was obtained in the other 

employed to fix or improve several other co- experiments of M. Gay Lussac Hydriodic 

lours. It is well known as an ingredient in add is partly decomposed at a red heat ; and 

ink. See Galls, Dyeing, Ink, and Salt, the decomposition is complete if it be mixed 

ACID (GLAUCIC). This substance, with oxygen. Water is fonned, and iodine 

considered as a new vegetable add, accord- separated.. 

ing to Dr Runge, occurs in several spedes M. Gay Lussac, in his admirable memcHr 

of the d^naeus and icaHota. It is a brittle on iodine and its combinatioas, published in 

ydlow mass, which reddens litmus and neu- the Ann. de Chimie^ vol. xd. says, that the 

trsUses ammonia. The tincture of the dry specific gravity he there gives for hydriodic 

plant in alcohol is treated with ether, which gas, viz. 4.443, must be a little too great, for 

throws down, white flocculL These, when traces of mdsture were seen in the inside of 

dissolved in water, are to be predpitated by the bottle. In fact, if we take 15.621 as the 

acetate of lead ; and the predpitate being de- prime of iodine to oxygen, whose spedfic 

.oooipoaed by sulphuretted hydrogen, affords gravity is 1.1111, and multiply one-half of 

a mixture of glaucic and acetic adds. Tlie this number by 15.621, as he does, we shall 

latter is easily separable by a moderate heat, have a product of 8.6696, to which adding 

ACID (OF THE GRASSHOPPER). 0.0694 for the density of hydrogen, we get 

JProbaMy a modification of the acetic add. the sum &7390, one^balf of which b ob- 

ACII)(HIRCIC). This,accordingtoM. riously the density of the hydriodic gas = 

Chevreul, is the product of the action of aU 4.3695. When the prime of iodine is taken 

lulls on a peculiar oil, which he calls hxrcinef ^ 15,5^ thea the density of the gas comes 

which he found combined with stearine and out 4.3. 

oleine in the fat of the goat and sheep. It We can easily obtain an aqueous hydriodic 

is cokmrless, liquid at 32^ F., emits the acid very economically, by passing sulphuret- 

smell of acetic add and that of the goat ; it ted hydrogen gas through a mixture of water 

reddens litmus; is hardly soluble in water, and iodine in a Woolfe's bottle. On heating 

but very soluble in alcoliol : it forms with the liquid obtained, the excess of sulphur flies 

potash a deliquescent salt, vrith baryta one off, and leaves Uquid hydriodic add. Attem- 

not very soluble in water, and with ammonia peratures below 262^ it parts with its water, 

a salt which emits more of the goat effluvia and becomes of a density := 1.7. At 262^ 

than the add itself. the add distils over. When exposed to the 

ACID (HYDRIODIC). This add re- air, it is speedily decomposed, and iodine is 
sembles the muriatic in being gaseous in its evolved. Concentrated sulphuric and nitric 
insulated state. If four parts of iodine be adds also decompose it When poured into 
mixed witb one of phosphorus, in a small a saline solution of lead, it throws down a 
glass retort, applying a gentle heat, and add- fine orange predpitate. With solution of 
ing a few drops of water from time to time^ peroxide of mercury, it gives a red predpi. 
a gas comes over, which must be received in tate ; and with that of silver, a white prfr. 
the mercurial bath. Its spedfic gravity is cipitate insoluble in ammonia. Hydriodic 
4.4; 100 cubic inches, therefore, wdgh 134.2 acid may also be formed, by passing hydro- 
grains. It is elastic and invisible, but has a gen over iodine at an elevated temperature. 
amdl somewhat similar to that of muriatic The compounds of hydriodic acid with the 
add. Mercury afler some time decomposes salifiable Ixises may be easily fonned, dther 
it, seizing its iodine, and leaving its hydro- by direct combination, or by acting on the 
gen, equal to onfr-half of the original bulk, basu in water, with iodine. Tlie latter mode 
at liboty. Chlorine, on the other hand, is most economical Upon a deternunate 
unites to its hydrogen, and precipitates the quantity of iodine pour solution of potash or 
iodine* From these experiments, it evident- soda, till the liquid ceases to be coloured, 
ly aoodats of vi^iir of ioditie and hydrogen. Evaporate to dryness, and digest the dry salt 



ACID 30 CHROMIC. 

tfacm which cannot be decompoaed by all the —A hot and oonoentnted solution of the bi- 
mineral adds, except the carbonic, and by the chromate of potash is to be decompoaed by 
greater part of the regetable acids; sothaton fluosilicic acid; the liquid is to be filtered 
pouring one of these acids into a solution of and cTaporsted to dryness ; the add thua 
the cholestetate, the chdesteric acid is in- dried is to be dissolved in as small a quantity 
stantly sepuwted in fiocka. The soluble cho- of water as possible^ and the clear fluid do- 
lestentes form precifutates in all the metallic canted from the deposit of fluosilicate of pot- 
solutions, whose baae has the property of ash which has passed the filter. Hie separa- 
ibrming an insoluble or slightly soluble salt tion of this portion must not be made by m 
with cholesteric acid. filter, for in this state the chromic add at- 

MM. PeDetier and Caventou found the cho- tacks the paper, and is itaelf converted into 

lesfeerate of baryta to consist of 100 of add, oxide of chrome. 

and 56,259 base; whence the prime equivalent To prepare the fluosilidc add in suffidem 
of the farmer appears to be about 17.35. Yet quantity, M. Maus uses a very laige retort 
they observed, on the other hand, that on with a long neck. He puts into it the mix- 
treating the dKricsterete of lead with sulphuric ture of fluor-spar and glass, and adds sulphur 
«dd, they obtained as much sulphate of lead ric add to about three times the amount of 
as of cholestente. From this experiment, the the fluor-apar in weight, and mixes the whole 
equivalent of the dry add would seem to be welL A large globe with a long neck is then 
5 : hence we may imagine, that when the provided, and a suflident quantity of water 
cholesteric acid unites to the oxide of lead, put into it ; the neck of the retort is intro- 
and in general to all the oxides which have a duced, the globe shaken to moisten the inte- 
sligbc aflinity for oxygen, there takes place rior with water, and the fluosilidc gas evolv- 
something similar to what happens in the re« ed by the application of heat When it 
action of oxide of lead and oxalic add. Jounu arrives in the gk>be it condenses in the water, 
de Pharm, liL 292, and as soon as the quantity of silica produced 
ACID (CHROMIC). This add was at retards the contact of the gas and water, the 
first extracted from the red lead ore of Siberia, globe is again shaken and 3ie operadon con- 
by treating this ore with carbonate of potash, tinned. In this way no gas escapes, and the 
and separating the alkali by means of a more water soon becomes saturated with the add ; 
powerful add. In this state it is impure, * the silica is easily separable, 
forming a red or orange-coloured powder, of a Chromic add is soluble in water, and crys* 
peculiar rough metallic taste. If this powder tallises, by cooling and evaporation, in long* 
be exposed to the action of light and heat, it ish prisms of a ruby red. Its taste is acrid 
kses its addity, and is converted into green and styptic. Its spedfic grarity is not ex- 
oxide of chrome^ giving out pure oxygen gas. actly known; but it always exceeds that of 

To obtain pure diromic add, we must distil water. It powerfully reddens the tincture of 

fluor-spar, chromate of lead (the ydlow pig- turnsole. 

ment), and sulphuric add (anhydrous ?) in a Its action on combustible substances is little 

leaden retort, when a gaseous mixture of known. If it be strongly heated with char- 

diromic and fluoric adds is evolved, that is coal, it grows black, and passes to the metallic 

readily absortMble by water. This mixed gas state without melting, 

affords a thick orange smoke, and on coming Of the adds, the action of the muriatic on 

in contact with air, deposits small red crystals it is tiie most remarkable. If this be distilled 

of chromic add. Ammoniacal gas introduced with the chromic acid, by a gentie heat, it is 

into this gas, contained in glass jan lined with readily converted into chlorine. It likewise 

resin, burns with explosion. Crystals of chro- imparts to it by mixture the property of dis- 

mic add are also decomposed in ammoniacal solving gold ; in which the chromic resembles 

gaswithaflashoflight, and become protoxide the nitric add. This is owing to the weak 

of chromium. Water, by absoibing this adhesion of its oxygen, and it is the only one 

mixed gas, acquires an orange tint ; from of the metallic acids that possesses this pn^ 

■which, by evaporation, pure chromic add is perty. 

obtained, the fluoric being volatilised. If the The extraction of chromic add from chrome 

gas be recdved in a deep and moistened pla- ore is also performed by igniting it with its own 

tinum vessel, it descends, saturates the water, wdght of nitre in a crucible. The residue is 

and is then entirely absori>ed by the fluoric lixiviated with water, which bdng then filtered 

acid, which is at length dissipated, the vessel contains the chromate of potash. On pourintg 

becoming filled with a red snow, consisting of into tiiis a littie nitric add and muriate of 

chromic acid. This crystalline matter, when baryta, an instantaneous predpitate of the 

heated to redness in a platinum dish, fuses, chromate of baryta takes place. After having 

explodes with a flash, and resolves itself into procured a certain quantity of this salt, it 

protoxide and oxygen. The crystals obtained must be put in its moist state into a capsule, 

from the water do not present this pheno- and dissolved in the smallest possible quantity 

menon. of weak nitric add. The baryta is to be 

M. Maus prepares chromic acid as follows : then precipitated by very dilute sulphuric 



ACID 



31 



CITEIC. 



acid, taking care not Co add an excets of it. 
When the liquid is found by trial to contain 
neither sulphuric acid nor baryta, it must be 
filtered. It now oonsista of water, with nitric 
and chromic adds. The whole is to be em. 
fxwated to dryness^ conducting the heat at the 
end so as not to endanger the decomposidon 
of the chromic acid, whTch will remain in the 
capsule under the form of a reddish matter. 
It must be kept in a glass phial well corked. 
Chromic aod, heated with a powerful add, 
becomes dmmuc oxide; while the latter, 
heated with the hydrate of an alkali, becomes 
dironoic add. As the solution of the oxide 
is greeOf and that of the add yellow, these 
transmutations become Tery remarkable to the 
eye. From Benefius's experiments on the 
combinations of the chromic add with baryta, 
and oxide of lead, its prime equivalent seems 
to be d.5 ; consisting of 3,5 chromium, and 
3b0 oxygen. See CuaomuM. 

It readily unites with alkalis, and is the 
only acid that has the •property of colouring 
its salts, whence the name chromic has been 
given it. 

Chromate of potsah is obtained from the 
ferriferous chrome ore, by igniting it with 
nitres as described above By careful eva- 
pOTaiion it may be obtained in crystals, tlie 
usual form of which is four-sided prisms ter- 
minated by dihedral summits, or oblique four- 
fided prismsb terminated by four-sided pyra> 
mids. Tbdr colour is bright yellow. Their 
taste is cooling and disagreeable. Water at 
60^ dissolves about half ite weight of this salt, 
and boiling water much more. It is insoluble 
in alcoboL Its spedfic gravity is 2.6. Heat 
onuses the salt to assume a transient red tint, 
which passes into yellow on cooling. It con* 
tains no water of crystallisation. Its constitu- 
ents are chromic add»6.5, potash 6, =3 12.5* 
To test chromate of potash, add a large ex- 
cess of tartaric add, which decomposes the 
chromic add, and gives the whole the ame- 
thystine hue of tartrate of diromium. If 
the chromate has been pure, this liquid will 
afford no |»«dpitate with the nitrates of ba- 
ryta or silver ; whence the absence of muri- 
ate or sulphate of potash may be readily as* 
ocrtainad. Nitre may be detected by the 
fiimes of nitric add disengaged by pouring a 
little sulphuric add on the nte. 

Bi-clirooiate of potash is easily formed, by 
adding to a saturated solution of the yellow 
dwomate some dilute nitric add. On beat^ 
ing the mixture, the orange predpitate, which 
ensues on the addition of the nitric add, is 
dissolved, and, by slow cooling, fine crystals 
of bi-duomate may be obtained. Their form 
is that of square tables with bevelled edges, or 
flat four-sided prisms. Tbey are permanent 
in the air. Their taste is metallic and bitter. 
Water at 60^ dissolves about one-tenth of 
this salt; but boiling water dissolves nearly 
half its weight. It is not soluble in alcohol. 



Its sp. gr. is 1.98. It is anhydrous. It. 
consists of chromic add 13, potadi 6, sss 19. 
Chromate of baryta is very little soluble. 
Mr Henry Stokes has described three new 
double chromates, obtslned by adding diro- 
mate of potash to sulphate of sine, and also to 
sulphate of nickel, and to sulphate of copper. 
They all contain very little chromic add, are 
pretty soluble in water, crystallize in tables, 
and undergo no diange in tbe atmosphere. 
In 100 parts of the zinc salt, there are only 
one^third of a part of chromic add, and not 
two parts in 100 of tbe nickel salt. 

When chromic add is melted with borax, or 
its glass, or add of phosphorus, it communi- 
cates to it a beautiful emerald-green colour. 

If paper be impregnated with it, and ex- 
posed to the sun a few days, it acquires a 
green c<dour, wtddi remains permanent in the 
dark. 

ACID (CHROMO-SULPHURIC).— 
When chromate of baryta is treated with di- 
lute sulphuric add in excess, the liquid, on 
being filtered and evaporated, lets fall little 
quadrangular prisms of a deep red colour. 
These crystals, which may also be obtained 
by mingling chromic and sulphuric acids in 
a proper state of concentration, are obvioua- 
ly a compound of the two adds in atomic 
proportions, stated by M. Gay Lussac at 
130a64 chromic add, and 501.16 sulphuric. 
By our numbers, there are thus two atoms 
of the chromic to one of the sulphuric add. 
This compound acid is deliquescent. When 
the alcoholic solution is highly concentrated 
it explodes, while tbe chromic add is con- 
verted into the green oxide of chrome, vrith 
the simultaneous production of a little suU 
phuric ether and sweet oil of wine. 

ACID (CHYAZIC). See Acnw (Hy- 
DBOCYANICand Fbbbocyanic). 

ACID (CITRIC). To procure tfaisacid, 
boiling lemon-juice is to be saturated with 
powdered dialk, the weight of which is to be 
noted ; and the powder must be stirred up 
from the bottom, or tbe vessel shaken from 
time to time. The neutral saline compound 
falls to the bottom, while the mudlage re*> 
mains suspoided in the watery fluid, which 
must be decanted off*; the remaining predpi- 
tate must then be wadied with warm water 
until it comes off^ clear. To the powder thus 
edulcorated, a quantity of sulphuric add, 
equal the chalk in wdght, and diluted with 
ten parts of water, must be added, and the 
mixture boiled a few minutes. The sulphu- 
ric acid combines with the earth, and forms 
sulphate of lime, which is 1^ when the 
cold liquor is filtered, while the disengaged 
add of lemons remains dissolved in the flukL 
This last must be evaporated to the consist*- 
ence of a thin syrup, which yields tbe pure 
dtric add in little needle-like crystals. It is 
necessary that the sulphuric add should be 
rather in excess, because the presence of a 



ACID 3i FLUORIC. 

Dr Thomion, in his dabonte work oa the liquid flnoric add. *< In this caae^ gas 

the first prindples of Chemistry, assigns 1.25 appeared to be produced from both the ne- 

as the prime equivalent of fluoric add. He ^itiTe and positive surfaces ; but it was pro- 

deducoi this number fipom the quantity of bably only the undecompounded add, reo- 

chloride of caldum, and of chloride of ba- dered gaseous, which was evolved at the pod- 

rium, to which a oertun vrdght of fiuate of tive surface ; for during the operation the 

soda was found to be equivalent in the way fluid became very hot, and speedily diminiah- 

of double decomposition. But his fluate of ed."-— << In the course of these invesdgationa 

soda was prepared in a very questionable I made several attempts to detadi hydrogen 

' manner ;-^y adding carbonate of soda in from the liquid fluoric add, by the agency of 

small quantities to a solution of carbonate of oxygen and chlorine. It was not deoompoeed 

ammonia, previously saturated with silicated when passed through a platina tube heated 

fluoric gas ; evaporating the whole to dry- red-hot with chlorine, nor by being d i stil W 

ness ; redissolving and evaporating till the from sdts contuning abundance of oxygen, 

fluate of soda crystallized in transparent or those contuning abundance of chlorine." 

crusts. • As a fluosilicate of ammonia exists, The marvellous activity of fluoric add may 

possibly some of thu may have been formed, be inferred from the foUovring Temarks of 

of which some silica might remain associated Sir H. Davy^ from which also may be esti- 

'with his soda. Nor does his fluate of soda mated in some measure, the prodigious diflif- 

correspond in character to the description of -culty attending refined investigations on this 

this salt direcdy formed by Berzelius, by sa- extnordinary substance, 

turating carbonate of soda with pure fluoric <* I undertook the experiment of dectris- 

add. By spontaneous evaporation, fluate of ing pure liquid fluoric add with considerable 

' soda is, obtuned in transparent cubes, or re- interest, as it seemed to offer the most probar 

gular octahedrons; by heat, in groups of ble method of ascertdning its real nature; 

small cubical grains. It contains no water but condderable difficulties occurred in exe- 

of crystallization, and is more difficult of cuting the process. Ihe liquid fluoric add 

fusion by heat than glass. At the tempera- immediately destroys glass, and all animal 

ture of 60^ F. 100 parts of water dissolve and vegetable substances; it acts on all 

only 4^ 8 parts of it; and at the bdling pdnt bodies contdning metallic oxides; and I 

only 4.3. Dr Thomson says, that he dis- know of no substances which are not rapidly 

solved 6.25 grdns of his sidt (white crusts, dissolved or decomposed by it, accept metals, 

fr-eed by ignition from thdr water of crysUU- charcoal, phoq[»horus, sulphur, and certain 

Szation) in a UtUe water. From the mode of combinations of chlorine. I attempted to 

preparing his primary sdt, from its appear- make tubes of sulphur, of muriates of lead, 

ance^ and from the defect in the process of and of copper contdning metallic wires, by 

double decomposition for forming pure fluate which it might be dectrized, but without suc- 

of lime, Dr Thomson's atomic number seems cess. I succeeded, however, in boring a piece 

entitled to little confidence. of horn diver, in such a manner that I was 

Fluoric add may dtfaer be regarded as a able to cement a pUtioa wire into it by means 

compound of oxygen with an unknown base of a spirit lamp ; and by inverting this in a 



to be cdled fluor ; or of hydrogen with an tray of platina, filled with liquid fluoric 

electro-n^^tive element to be cdled fluorine. I contrived to submit the fluid to the agency 

If fluor-spar condst of lime associated with of dectridty in such a manner, that, in aoo- 

an oxygen add, then this will contdn one cesdve experiments, it vras possible to collect 

prime proportion of oxygen ss 1, combined any elastic fluid that might be produced, 

with one prime of fluor = 0.357. Were Operating in this way with a yery vreak voU 

this latter number 0.375, to which it ap- tdc power, and keeping tlie apparatus cool 

proaches, it would equal the wdght of three by a freedng mixture, I ascertained that the 

atoms of hydrogen. But if fluor-spar be platina wire at the podtiye pole rapidly cor- 

truly a fluoride of cdcium, then, frvnn its roded, and became covered with a chocolate 

prime equivalent 4.857, we deduct the prime powder ; gaseous matter separated at the ne- 

equivdent of cdcium 2.5, and the remdnder gative pole, which I could never obtain in 

2.357 will be the prime of fluorine, a number suffidentquantities to andyze with accuracy, 

nearly 19 times that of hydrogen. but it inflamed like hydrogen. No other in- 

From the remarkable property possessed by *flammable matter was produced when the 

fluoric acid of dissolving dlica, it has been add was pure." M. Kuhlmann transmitted 

employed for etching on glass, botli in the anhydrous sulphuric add in vapour, over 

gaseous state and combined with water. The ignited fluor-spar contdned in a platinum 

glass is previously coated with white bees' tube, but no change ensued. The acid was 

wax ; on which the figures are traced with a recondensed in part in the farthest tube, and 

sharp pomt. no trace of fluoric acid was perceptible. 

With the view of separating its hydrogen. But when a little water vras added to the 

Sir H. Davy applied the power of the great sulphuric add, the fluoric was instantly dis- 

vdtdc batteries of the Royal Institution to engaged frtnn the spar. 



ACID 36 FLU08ILICIC. 

Hit nm^ chemist dflcbmposed fluorspar 4)f soda mehi with more difliciilty than gUn. 

by tmnmittnig dry muriatic add gas over it 100 parts of water at 6(F F. dissoWe 4.8 of 

ignited io a tubc^ Chloride of lime remain* it; and at the boiling point only 4i.3* 

ed in the tulw, and pure bTdrofluorie gas AcidfiuaU of ammonia fonns small gra- 

came over. 100 parts of the fluoride of nular crystals, which deliquesce. 

cahaum (fluor-spar), thus treated, became JVrtc/m/^iMfe of oinmoMia is more volatile 

143.417 parts of chloride of caldum, con- than sal ammoniac. It is easily obtained by 

sisting of 52.819 parts of caldum, (present heating one part of dry sal ammoniac with a 

in 100 of fluor-spar), united to 90.598 of little more than two parts of fluate of soda, 

chlorine). But this latter quantity must in a crudble of platinum with its lid turned 

have liberated 2.51 1 parts of hydrogen, says upwards. Into this lid a little cold water is 

fiC. Kuhlmanuy which must therefore have put, while the bottom of the crudble is heat- 



with the 47.181 parts of fluorine ed with a spirit of wine lamp. The fluate of 
in the qiar, to form 49.692 parts of hydro- ammonia thus sublimes perfectly pure in a 



fluoric add. This must consist then of mass of small prismatic crystals. It fuses be- 

94^941 parts of fluorine, and 5.069 hydro- fore subliming, and acts on glass even in its 

gen, in 100. dry states and at ordinary temperatures. 

The salts formed by fluoric add and se- The earthy fluates are best prepared by 

versl bases, have been lately examined by M« digesting thdr recently predpitated moist 

Berselius with his accustomed predsicm. carbonates in an excess of fluoric add. That 

Smperjluate of poiath. Hiis add fluate is of baryta is slightly soluble in water, and 
obtained by mixing vrith the add a quantity of readily in muriatic acid, 
potash, insttflident to saturate it On con- ACID (FLUOSILICIC). If instead of 
centrating the solution, a little of the redun- bdng distilled in metallic vessels, the mixture 
dant add flies off*, but the greater part re- of fluor-spar and oil of vitriol be distilled in 
mains and crystallixes with the alkali. This glass vessels, little of the corrosive liquid will 
aalt, when horted, fuses, and leaves 74.9 per be obtained ; but the glass will be acted upon, 
cent of neutral fluate^ while fumes of fluoric and a peculiar gaseous substance will be pro- 
add are. volatilized. Berselius regards the duced, which must be collected over mercury. 
ahove add salt as composed of an atom of llie best mode of procuring this gaseous body 
fluate of potash, and an atom of hydiated is to mix the fluor-spar with pounded glass or 
fluoric add* quartz ; and in this case, the glass retort may 

Fluate ofpotath is prepared by saturating^ be preserved from corrosion, and the gas ob- 

imperfectly, fluoric acid with carbonate of tained in greater quantities. This gas, which 

potsah, evaporating and heating so as to expd is called silicated fluoric gas, is po s s esse d of 

the excess of add. It has a sharp saline very extraordinary properties. 

tasie^ is very alkaline^ and deliquesces in the It is very heavy ; 100 cubic inches of it 

air. It crystallizes very difficultly in water, weigh 1 10.77 gr. ; and hence its sp. gr. is to 

and then forms cubes or rectangular prisms, that of air as 3.638 is to I.OOO. It is about 

with stair-iike scales, similar to common salt 48 times denser than hydrogen. When 

^ddfluait ofioda. This salt is little so- brought into contact with water, it instantly 

luUe in odd water. By a slow spontaneous deposits a white gelatinous substance, which 

evi^Miration it affords rfaomboidal crystals, is hydrate of silica ; it produces white fumes 

having a sharp taste^ and distinctly add. when suffered to pass into the atmosphere. It 

Heat aeparatea the fluoric add in a concen- is not affected by any of the common com- 

trated states without changing the form of bustible bodies; but when potasnum is 

the crystals, and 68^ 1 per cent of neutral strongly heated in it, it takes Are and bums 

fluate remain. Berselius coosiders this salt with a deep red light ; the gas is absorbed, and 

to be a compound of an atom of fluate of a fawn-coloured substance is formed, which 

soda, and an atom of hydrated fluoric add. yields alkali to water with slight effervescence^ 

NewUralfiuate of soda. Thu salt may be and contains a combustible body. The wash- 
obtained directly nom fluoric add and car- ings afford potash, and a salt, from which the 
bonate of soda, or by decomposing 100 parts strong add fluid previously described may be 
of the double fluate of soda and silica, by 1 12 separated by sulphuric add. 
parts of dried carbonate of soda. When the Hie gas formed by the action of liquid 
aalt is pure, and left to spontaneous evapora- sulphuric add on a mixture containing sDica 
tion, it affords transparent cubes of r^^lar and fluor-spar, the silicated fluoric gas or fluo- 
octahedrons, which often present a pearly silicic add, may be regarded as a compound 
lustre, Octahedrons are always obtained of fluoric add and silica. It affords, when 
when the solution contains some carbonate decomposed by solution ofamroonia, 6 1.4 per 
of soda, but on the contrary, groups of small cent of silica ; and hence was at first sup- 
cubic grains when the evaporation is pro- posed by Sir H. Davy to consist of two prime 
duced by elevation of temperature. The proportions ofadd = 2.652, and one of silica 
fluates of potash and soda are iaomorphous s=r 4.066, the sum of which numbers might 
with the muriates of the same basest Fluate represent its equivalent ^ 6.718. One 



ACID 



36 



FLtJOBORia 



Toliime of it condenses two volumes. of am- 
monia, and they form togeCber a peculiar 
saline substance, which is decomposed by 
water. The composition of thi» salt is easily 
reconciled to the numbers given as represents 
ing ulica and fluoric acid, on the supposition 
that it contains one prime of ammonia to one 
of the fluosilicic gas ; for 200 cubic indies of 
ammonia weigh 36.2 gr. and 100 of the add 
gas 1 10.77. Now 36.2 : 2.125 : : Iia77 : 
6.5024. 

Dr John Davy obtained, by exposing that 

gas to the action of water, ^ 'aVo of its weight 
of silica; and from the action of water of 
ammonia he separated r VoV of its weight. 
Hence 100 cubic inches consist by weight of 
68 silica and 42 of unknown fluoric matter, 
the gas which holds the silica in solution. Sir 
H. Davy, however, latterly, concdves that 
this gas is a compound of the bases of silica, 
or silicon, with fluorine, the supposed basis of 
fluoric acid. 

Benelius, in his late elaborate researches on 
the fluoric combinations, (^nnales de Chim* 
et de Phy$, xzvii. 289.), says that the silicated 
fluoric acid should be regarded as nothing else 
than fluate of dlica, for it is only with the 
neutral fluates that it can unite without suf* 
fering decomposition ; and that when a portion 
of silica has been separated from it, it can be 
replaced only by an alkali, an oxide, or water. 
When he put iilicated fluoric gas in contact 
with carbonate of potash or soda, reduced to a 
very fine powder, there was no more of it ab- 
sorbed than what might be ascribed to mois- 
tuxe contained in the carbonate ; and the salt, 
after exposure to the gas for several days, had 
absorbed but an extremely small portion of it. 
Hie same result is observed with pure lime 
and the bicarbonate of potash. But the gas 
is very easily absorbed when exposed, even 
without moisture, to a finely pulverized fluate^ 
other with an alkaline^ earthy, or metallic 
base. At the end of a few hours, the fluate 
is completely satuiated with the gas ; showing 
that the portion oi fluoric acid and silica ab- 
sorbed, has no need of any new base for its 
saturation. This simple fact shows that the 
pretended fluosilicates, instead of being com- 
binations of a fluate with a silicate, are 
rather combinations of fluate of silica with 
fluates of the other bases. M. Berzelius 
infiers from his experiments, that fluate of 
silica is finrmed of 100 parts fluoric arid, 
and 144b 5 silica. Water separates one-third 
of this silica. 

ACID (FLUOBORIC). If, instead of 
glass or dlica, the fluor-spar be mixed with dry 
vitreous boradc add, and distilled in a glass 
vesel with sulphuric acid, the proportions be- 
ing one part boradc acfd, two fluor-spar, and 
twelve oil of vitrid,, the gaseous substance 
formed u of a difierent kind, and is called the 
fluoboric gas. TOO cubic inches of it we^h 
73b 5 gr. according to Sir H. Davy, which 



*Biak«8 its density be to that of air as S.4I is 
to 1.00 ; but Dr John Davy states its density 
to that of air as 2.371 to 1.000. It is 
colourless; its smdl is pungent, and resem^ 
bles that of muriatic arid; it cannot be 
breathed without suffocation ; it extinguishes 
combustion; and reddens strongly the tincture 
of turnsole. It has no manner of action on 
glass, but a very powerful one on v^etable 
and animal matter : it attacks them with as 
much force as concentrated sulphuric add, 
and appears to operate on these bodies by 
the production of water ; for while it carbo- 
nizes them, or evolves carbon, they may be 
touched without any risk of burning. Ex- 
posed to a high temperature, it is not decom- 
posed; it is condensed by cold without 
changing its form. When it is put in contact 
with oxygen, or air, either at a high or low 
temperature, it experiences no change^ except 
sdzing, at ordinary temperatures, the moisture 
which these gases contain. It becomes in 
consequence a liquid which emits extremely 
dense vapours. It operates in the same way 
with aU the gases whidi contain hygrometric 
water. However little they may contain, it 
occasions in them very perceptible vapours. 
It may hence be employed with advantage to 
show whether or not a gas containa moisture. 

No combustible body, simple er compound, 
attacks fluoboric gas, if we except the alkaline 
metals. Potassium and. sodium, with the aid 
of heat, bum in this gas almost as brilliantly 
as in oxygen. Boron and fluate of potash 
are the products of this decomposition. It 
might hence be inferred, that the metal sdzes 
the oxygen of the boradc add, sets the boron 
at liberty, and is itself oxidized and com- 
bined with the fluoric add. According to 
Sir H. Davy*s views, the fluoboric gas being 
a compound of fluorine and boron, the pot- 
assium unites to tiie former, giving rise to 
the fluoride of potassium, while the boron re- 
mains disengaged. 

Fluoboric gas is very soluble in water. Dr 
John Davy says, water can combine with 700 
times its own volume, or twice its wdght at 
the ordinary temperature and pressure of the 
air. The Uquid has a spedfic gravity of 
1.770. If a bottie containing this gas be 
uncorked under water, the liquid will rush in 
and fill it with explosive violence. Water 
saturated with this gas is limpid,, fuming, and 
very caustic.^ By beat about one-fifth of the 
absorbed gas may be expelled; but it is im- 
possible to abstract more. It tlien resembles 
concentrated sulphuric acid, and boils at a 
temperature considerably above 212^. It 
afterwards condenses altogether, in striiti al- 
though it contains still a very lai^ quantity 
of gas. It unites with the bases, forming 
salts caUed fluoborates, none of which has 
been applied to any use. Hie most impoiw 
tant will be stated under the artide Salt. 

The 2d port of the FhiL Transactions fo* 



ACID 



37 



FULMINIC. 



161S» MOtains an ezoeUent ptper by Dr John 
Ihirj tm fluosOicic and fluoboric gases, and 
thecambinations of the latter with annnoniacal 
gai» When united in equal v(dumes» a pul- 
verulent salt is formed ; a second Tolume of 
ammonia, however, g^vea a liquid compound ; 
and a third of ammonia, which is the limit of 
comliination, afibrda still a liquid; both of 
them curious oh many accounts. " They 
are^*' aays he^ « the first salts that have been 
obaerved liquid at the common temperature 
4if the atmosphere. And they are additional 
Acts in sui^Mnt cf the doctrine of definite 
proportions, and of the relation of volumes." 
ACID (FLUOTANTALIC). Hiis 
add is prepared in a similar way to the fol- 
lowing ; and forms, with tiie bases, salts call- 
hdjiuotanialates. 

ACID (FLUOTITANIC). When fluo- 
ric add is poured on titanic acid, the latter 
becomes warm, even after having been preri- 
ously ignited, and dissolves completely with 
Che aid of heat Evaporated at a gentle heat 
to the consistence of syrup, the s^ution a£- 
Ibrds crystals, which do not redissolve com- 
pletely in water, but which are decomposed 
into two peculiar combinations, of which one 
is addukius and soluble, and the other with 
«ices8 of base is insoluble. Tlie solution of 
die former, namely of the fiuotitanic add, in 
water, is malogous to the liquid fluosilidc 
add ; it contains fiuotitanic add, and fluoric 
add combined with water. Hie water may 
be replaced by other bases, and in this way 
may be formed a series of salts which M. Ber- 
adius calls fiuolUanaUs. The fiuoHlanate 
qf potash crystallises in brilliant scales like 
bondc add, which redissolve in water with- 
out decompositioD. It consists in 100 parts 
4if potash 3S,7, titanic add 3S^ and fluoric 
acid2aa 

ACID (FORMIC). To procure pure 
formic acid, Gehloi saturates the expressed 
liquor of ants with subcarbonate of potash, 
pours into the compound sulphated peroxide 
•of iron, filters, evaporates to the consistence 
of syrup, and distils in a glass retort, with a 
suflident quantity of sulphuric add. The 
product which passes into the recdver is very 
sour, and without any perceptible odour oif 
sulphurous add. He then puts it in contact 
irith carbonate of copper, evaporates the so- 
lution, and procures fine blue crystals, which 
he considers as formiate of copper. From 
this be extracts the pure and the most con- 
centrated add possible, by decomposing the 
salt irith two-thirds of its wdgbt of sulphuric 
add, aided by heat, distilling it into a re- 
ceiver, and rectifying by a second distillation. 
From thirteen ounces of formiate thus treated, 
he obtained more than six ounces and a half 
of pure formic add. 

Hns add baa a very sour taste^ and con- 
tinues liquid even at very low temperatures. 
Itsspedfic gravity is 1.1 168 at e^, which is 



much denser than acetic add ever is. Berze^ 
lius finds, that the formiate of lead consists of 
, 4k696 add, and 14 oxide of lead; and that 
the ultimate constituents of the drj add are 
hydrogen 2.84 4- carbon 32.40 4- oxygen 
64.76 =100. 

M. Dobereiner has recently succeeded 
(See Gilbert's Annales, xi. 107.) in forming 
this add artifidally. When a mixture of tar- 
taric add, or of cream of tartar, black oxide 
of manganese and water, is heated, a tumul- 
tuous action ensues, carbonic add is evolved, 
and a liquid acid distils over, which, on su- 
perficial examination, was mbtaken for acetic 
add, but which now proves to be formic acid. 
This add, mixed with concentrated sulphuric 
acid, is at common temperatures converted 
into water and carbonic oxide ; nitrate of sil- 
ver or of mercury converts it, when gently 
heated, into carbonic acid, the oxides bdng 
at the same time reduced to the metallic 
state. With baryta, oxide of lead, and oxide 
of copper, it produces compounds having all 
the properties of the genuine formiates of 
these metals. If a portion of sulphuric add 
be employed in the above process, the tartaric 
add is resolved entirely into carbonic acid, 
water, and formic acid ; and the product of 
the latter is much increased. The best pro- 
portions are, two parts tartaric add, five per- 
oxide of manganese, and five sulphuric add 
diluted with about twice its weight of water. 
M. Doberdner finds, that when formic 
add is decomposed by sulphuric acid, it b 
resolved into 24.3 water, and 75.7 carbonic 
oxide, in 100 parts ; or of one volume of 
vapour of water, and two volumes carbonic 
oxide gas ; or two atoms carbon, three oxy- 
gen, and one hydrogen. 

ACID (FULMINIC). Put aS parts 
of nitric add, sp. gravity 1.36 or 1.38, into 
a pint matras, and a piece of coin contain- 
ing nearly 35 parts of pure silver. Pour 
the resulting solution into about 927 parte 
of strong alcohol, and heat to ebullition. 
On the appearance of turbidness, remove 
from the fire, and add by degrees an equal 
quantity of alcohol to the solution, in order to 
moderate tlie ebullition, and to cool it Fil- 
ter it when cold, and wash away the whole 
free add. The fulminate of silver is now pure 
and white as snow. Dry it in a steam heat 
for two or tiiree hours, after which it will be 
found to equal in wdght the silver employed. 
A slight blow between hard bodies explodes 
it It may be analyzed by nibbing it with 
the finger with forty times ite wdght of per- 
oxide of copper, and igniting the mixture in 
a glass tube. 100 parts of it, analyzed in 
this way, afforded 77.528 of oxide of silver. 
The add associated with this oxide is the cy- 
anic. Hence the ultimate constituents are, 
in 100 parts, silver 72.187, oxygen 5.341, 
C3ranogen 17.16, oxygen (combined with the 
silver) 5.312. It consists, therefore, of one 



ACID 



46 



HYDROCYANIC 



and thoracic organs. It was bat aUf^y 
penrepUble in the ttomach, which contained 
nothing but mucus ; but on cutting the or- 
gan in pieces, it was dereloped* The sto- 
mach was cut into pieces under water, and 
distilled with the water. When about an 
eighth of the liquid had passed over, it was 
mixed with potash and persulphate of iron, 
and soon gave a feeble blue tint, leaving no 
doubt of the presence of hydrocyanic acid. 
The test by copper gave it still more sensi- 
bly. The copper detected prussic acid also 
in the intestines ; but the persulphate of iron 
did noL Aqueous chlorine has been found to 
be an antidote to the pcnaon of prussic acid. 

Having been consulted by physicians and 
apothecaries concerning the strength of the 
dilute hydrocyanic acid employed in medi- 
cine, I instituted a series of experiments, to 
determine the relation between its specific 
gravity and quantity of real add. The add 
which I prepared with this view had a q>eci* 
fie gravity s= 0.957. 

Hie following table comprehends 
results. 



Quaaaty of above 
Liquid Add. 




RmlAdd 
percent 


100.0 


0,9570 


16 


66.6 


0.9768 


10.6 


57.0 


0.9815 


9.1 


50.0 


0.9840 


8.0 


44^4 


0.9870 


7.3 


40.0 


0.9890 


6.4 


36.4 


0.9900 


5.8 


3a3 


0.9914 


5.3 


30.8 


0.9923 


5.0 


28.6 


0.9930 


4.6 


25.0 


0.9940 


4.0 


22.8 


0.9945 


3.6 


20.0 


0.9952 


3.2 


ia2 


0.9958 . 


ao 


16.6 


0.9964 


2.7 


15.4 


a9967 


2.5 


14.3 


0.9970 


2.3 


13.3 


0.9973 


2.1 


12.5 


0.9974 


2.0 


11.8 


0.9975 


1.77 


10.5 


0.9978 


1.68 


10.0 


0.9979 


1.60 



- From the preceding table it is obvious, 
that for add of spedfic gravity 0.996 or 
0.997, such as is usually prescribed in medi- 
dne, the density is a criterion of greater 
nicety than can be convenientiy used by the 
majority of practitioners. In fact, the liquid 
at 0.996 contains about double the quantity 
of real add which it does at 0.998. It is 
therefore desirable to have another test of the 
strength of this powerful and dangerous me- 
didne, which shall be easier in use, and more 
ddicate in its indications. Such a test is 
afforded by the red oxide of mercury, the 
common red predpitate of the shops. The 



prima equivalent of prussic add is ekacdy 

ono^eighth of that of the mercurial peroxide* 
But as the prussiate of mercury consists of 
two primes of add to one of base, or is, in 
its dry crystalline state, a bicyanide, we have 
the relation of one to four in the formation 
of that salt, when we act en the peroxide 
with cold pnudc add. Hence we derive 
the following simple rule of analyaia. - To 
100 grains, or any other convenient quantity 
of the acid, omtained in a small phial, add 
in succession small quantities of the peroxide 
of mercury in fine powder, till it ceases to be 
diasolved on agitation. The wdght of the 
red precipitate taken up being divided by 
four, gives a quotient representing the quan- 
tity of real prussic add present. By wdgh- 
ing out beforehand, on a piece of paper or 
a watch-pglass, forty or fiily grains of the 
peroxide, the residual weight of it shows at 
ooce the quantity expended. 

The operation may be always oom[deted 
in five minutes, for the red predpitate dis- 
solves as rapidly in the dilute prussic add, 
with the aid of slight agitation, as sugar dis- 
solves in water. Should the presence of mu^ 
riatic add be suspected, then the sped^c gra- 
vity of the b'quid bdng compared with the 
numbers in the above tsble, and with the 
weight of peroxide dissolved, will show how 
far the suspicion is well founded. Hius, 
if 100 grains of add, sped6c grarity 0.996» 
dissolve more than 12 gndns of the red pre- 
dpitate, we may be sure that the liquid haa 
been contsminated with muriatic add« Ni- 
trate of silver, in common cases so valuable 
a reagent for muriatic add, is unfiirtunately 
of little use here ; for it gives with prussic 
add a flocculent white predpitste, soluble in 
water of ammonia, and insoluble in nitric 
add, which may be easily mistaken by com* 
mon observers for the chloride of that metaL 
But the difference in the volatility of pnia- 
aiate and muriate of ammonia may be had 
recourse to with advantage ; the former ex- 
haling at a very gentie heat, the latter requir- 
ing a subliming temperature of about 300^ 
Fahrenhdt. After adding ammonia in slight 
excess to the prussic add, if we evaporate to 
dryness at a heat of 212^, we may infer from 
the residuary sal ammoniac the quantity of 
muriatic add present . 

Tlie preceding table is the result of experi- 
ments which I made some time ago at Glas- 
gow. I have latdy verified its accuracy by 
experiments made at the Apothecaries* Hall, 
London, on thdr pure prussic add. 100 
grains of the bicyanide of mercury requirs 
for their conversion into bichloride (corrosive 
sublimate), 28.56 grains of chlorine^ a quan- 
tity to be found in 100 grains of muriatic 
add, spedfic grarity 1.14^2. And as 100 
gndns of the bicyanide afford 20.6 of real 
prussic add, they will Aimish, by careful dis- 
tillation on a vrotar bath, a quantity of liquid 



ACID 47 CYANIC. 

acid» eqatnleot to 700 grains of tfie medici- prussiate of potash and iron. In illustration 

nal stxcngCh 0.996L By consulting my table of this view, he prepared a hydrocyauate of 

of muriatic acid, published in this Diction- potash and silver, which was quite neutral, 

mrjt the quantity of it at any density, neces- and which crystallized in hexagonal plates. 

saiyibrdecompasing the above cyanide, will The solution of these crystals precipitates 

be iniHiediately found ; bearing • in mind, salts of iron and copper white. Muriate 

that 31.5 SB the prime equivalent of the salt, of ammonia does not render it turbid ; but 

carrespoods to 9 of chlorine. muriatic acid, by disengaging hydrocyanic 

Sdieele found that pruasic acid occasioned acid, precipitates chloride of silver. Sulphu- 

pfccipitaties with only the following three retted hydn^n produces in it an analogous 

metallic aolutions; nitrates of silver, and change. This compound, says M. Gay 

mereury, and carbonate of silver. The first Lussac, is evidently the triple hydrocyauate 

is white, the second black, the third green, of potash and silver ; and its formation 

becoming blue. ought to be analogous to that of the other 

Hie hydiocyanates are all alkaline, even triple hydrocyanates. " And as we cannot 

when A gnat excess of add is employed in doubt," adds he, " that hydrocyanate of 

their fonnation ; and they are decomposed by potash and silver is in reality, from the mode 

the weakest adds. ^ its formation, a compound of cyanide of 

The hydrocyanate of ammonia crystallizes silver and hydrocyanate of potash, I conceive 

in cubes, in ff«"*ll prisms crossing each other, tliat the hydrocyanate of potash and iron is 

or in feathery crystals, like the leaves of a likewise a compound of neutral hydrocy- 

fan. Ita volatility is such, that at the tem^ anate of potash, and subcyanide oif iron, 

pe»tare of 71^° it is capable of bearing a which I believe to be combined with hydro- 

pRssureoff 17.72 inches of mercury; and at* cyanic acid in the white predpitate. We 

970 jis elaatidty is equal to that of the atmo- nuiy obtain it perfectly neutral, and then it 

sphoe. Unfortunately this salt is charred does not decompose alum; but the hydro- 

and decomposed with extreme iadlity. Ita cyanate of potash, which is always alkaline, 

great volatility prevented M. Gay Lussac produces in it a light and flocculent pred- 

fiom determining the proportion of ita con- pitate of alumina. To the same excess of 

stituenls. Hydrocyanic add converta mm alkali we must ascribe the ochry colour of 

or ita oxide into prusoan b)ue^ without the the predpitates which hydrocyanate of potash 

hdp cither of alkalis or adds. Cyanogen forms with the persalta of iron. Hius die 

acta on iron and water as iodine dj^es on remarkable fact, which ought to fix tlie at- 

water and a base ; and a cyanic add is tention of chemists, and which appears to 

formed, which (fissolves a part of the iron, me to overturn the theory of Mr Porrett, in, 

but also and at the same time hydrocyanic that hydrocyanate of potash cannot become 

arid, whkh changes another part of the iron neutral except when combined with the cya- 

into Prussian blue. nides." 

According to M. Vauqoelin, very complex ACID (CYANIC). Cyanate of potash 
changes take pkce when gaseous cyanogen is may be procured in large quantity by heet- 
Gombincd with water, which leave the nature ing to dull redness a very finely pulverized 
of the above add involved in some obscurity, mixture of about equal parte of ferrocyanate 
The water is decomposed: part of ita hydro- of potash (well dried) and peroxide of man- 
gen combines with one port of the cyanogen, ganes& If the heat be too great, we shall 
and fonns hydrocyanic add ; another part obtain little salt, because the deutoxide form- 
unites with the nitrogen of the cyanogen, ed appears to change into protoxide at the 
and forms ammonia; and the oxygen of the expense of the cyanate. The mass is to be 
water forms cazbonic add, vrith one part of boiled with alcohol of moderate strength 
the caiix»n of the cyanogen. Hydrocyanate, (0.840 sp. gr.), and on cooling, the salt sepa- 
caibomrte^ and cyanate of ammonia, are also rates in small plates, resembling chlorate of 
found in the liquid; and there still remain potash. It is insoluble in pure alcohoL 
some cavljbn aiyi nitrogen, which junduce Cyanate of potash acted on by muriatic 
a brown deposit. Four and a half parts of add gas is converted into chloride of potaa- 
water absorb one of gaseous cyanogen, which sium, and much sal ammoniac is developed, 
oommnnicate to it a sharp taste and smell, Cyanate of potash, by simple boiling in wa- 
but no colour. The solution in the course ter, becomes carbonate of potash. By both 
of some days, however, becomes yellow, and modes o£ analysis it seems to consist of 
afterwards brown, in consequence of the potash 57.95, add 42.05; whence the prune 
intestine changes rekted above. equivalent of the add would seem to be 
Hydrocyanic add is separated from potash 4.45. 100 of cyanate of silver contain 
by carbonic add ; but when oxide of iron.is 77.353 of oxide; a statement agredng 
added to the potash, M. Gay Lussac concaves nearly with the above equivalent, 
that a triple compound, united by a much The cyanates acted on by aqueous adds, 
more energetic affinity, results, constituting give out their carbon of composition in the 
.what is usually called prasiiate of potash, or form of carbonic, add. In this way, the add 



ACID 



48 



CHLOROCTANIC 



cuo siitu ent of cyanate of nlTOr wai analyied, 
and fbund to contain, carbon 35,S34i, aaoCe 
41.317, and oxygen 23.349; or cyanogen 
76.65 1, oxygen 2^349. In fact, 2 atoms of 
carbon sss 1.5, -|* 1, axote =r 1.75, 4- h oxy- 
gen =s 1 , give a sum ss 4.25 ; which* con- 
Terted into per cent proportions are, carbon 
35.3, azote 41.7, oxygen 23.53 ss 100. 
Hence this add has tlie same composition as 
the folminic acid, though its properties are 
▼ery difierenL — F, fTdhler, Ann. de Ckm, 
ei de Pkys. xxviL 196. 

M. Liebeg states, that cyanic add may be 
obtained in a separate state, by passing a 
current of sulphuretted hydrogen gas through 
water in which cyanate of silver is diffused. 
Hie acid reddens litmus strongly ; is sour to 
the taste; it possesses the smell which is 
always percdved when any of its salts are 
decomposed by an acid ; it neutralizes bases 
perfectly, but when in contact with water it 
suffers decomposition in a few hours, and is 
converted into carbonic acid gas and ammo- 
nia. The sulphuretted hydrogen must not be 
passed so long as to decompose all the cyanate 
of silver; for then the cyanic add is eon- 
verted into other products by the excess of 
the sulphuretted hydrogen. See Acio ( F(7I^ 

ACID (CHLOROCYANIC). M. Ber- 
thoUet discovered, that when hydrocyanic 
add is mixed with chlorine, it acquires new 
properties. lu odour is much increased. 
' It no longer forms prussian blue with solu- 
tions of iron, but a green predpitate, which 
becomes blue by the addition of sulphurous 
add. Hydrocyanic acid thus altered had 
acquired the name of osyjrruatiCf because it 
was supposed to have acquired oxygen. M. 
Gay Lussac subjected it to a ndnute exami- 
nation, and found that it was a compound 
of equal volumes of chlorine and cyanogen, 
whence he proposed to distinguish it by the 
name of chlorocyanic add. To prepare this 
compound, he passed a cunrent of chlorine 
into solution of hydrocyanic add, till it de- 
stroyed the colour of sulphate of indigo ; and 
by agitating the liquid with mercury, he 
deprived it of the excess of chlorine. By 
'distillation, afterwards, in a moderate heat, 
an elastic fluid is disengaged, which possesses 
the properties formerly assigned to oxjfprussic 
ad<L This, however, is not pure chlorocy- 
anic add, but a mixture of it with carbonic 
add, in proportions which vary so much as 
to make it difficult to determine them. 

When hydrocyanic add is supersaturated 
with chlorine^ and the excess of this last is 
removed by mercury, the liquid contains 
chlorocyanic and muriatic acids. Having 
put mercury into a glass jar until it was 
3-4ths full, he filled it completely with that 
add liquid, and inverted the jar in a vessel 
of oMKury. On eihanaring the recdver of 



cnrjr sunk in the jar, in conaa qu ence of the 
elastic fluid disengaged. Bj degrees the 
L'quid itself was entirely expelled, and swam 
on the mercury on the outside. On admit- 
ting the air, the liquid could not enter the 
tube, but only the mercury, and the whole 
elastic fluid condensed, except a small bubble. 
Hence it was concluded that chkno^anic 
add was not a permanent gas, and that, in 
order to remain gaseous under the pressure 
of the air, it must be mixed with another 
gaseous substance. 

The mixture of chlorocyanic and carbonic 
adds, has the following properties It is 
colourless. Its smell is very strong. A very- 
small quantity of it irritates the pituitovy 
membrane^ and occasions tears. It reddens 
litmus, is not inflammable, and does not de- 
tonate when mixed with twice its bulk of 
oxygen or hydrogen. Its density, deter- 
mined by calculation, is 2. 1 1 1. Its aqueous 
solution does not predpitate nitrate of silver, 
nor baryta water. libe alkalis absorb it 
rapidly, but an excess of them is neoessarj 
to destroy its odour. If we then add an 
add, a strong effervescence of carbonic add 
ia produced, and the odour of chlorocyanic 
add is no longer peicdved. If we add an 
excess of lime to the add solution, ammonia 
is disengaged in abundance. To obtain the 
green predpitate from solution of iron, we 
must begin by mixing chlorocyanic add witb 
that solution. We then add a little potash, 
and at last a little add. If we add the 
alkali before the iron, we obtain no green 
predpitate. 

M. Gay Lussac deduces for the composi- 
tion of chlorocyanic add 1 volume of carbon 
4- i a volume of aaoCe 4~ i * volume of 
chlorine; and when deoompoeed by the suc- 
cessive action of an alkali, and an add, it 
produces one volume of muriatic add gas -f- 
1 volume of carbonic add 4~ ^ volume of 
ammonia. The above three elements sepe- 
ratdy constituting two volumes, are con- 
densed, by forming chlorocyanic add into 
one volume. And unce one volume of 
chlorine^ and one volume of cyanogen, pro- 
duce two volumes of chlorocyanic add, the 
density of this last ought to be the half of 
the sum of the densities of .its two consti- 
tuents. Density of chlorine is 2.421, den- 
sity of cyanogen 1.801, half sum = 2. 1 1 1, 
as stated above: Or the proportions by 
wdght wili be 3.25 = a prime equivalent 
of cyanogen 4- ^5 s= a prime of chlorine^ 
giving the equivalent of chlorocyanic add 
» 7.75. 

Chlorocyanic add exhibits with potassium 
almost the same phenomena as cyanogen. 
The inflammation is equally slow, and the 
gas diminishes as much in volume. 

Serullas prepares chlorocyanic add as fol- 
lows :— He fills a lai^ge matress with chlo- 
rine^ and then introduces into it, for every 



ACID 



48 



FERROCYANIC. 



ten cidae iocfaes of ga>» trnxOy-Honr gnuns 
of csfinideof mercuiyi |niWeriaEed and moist 
The matms is now corked, and set aside for 
ten or twelve hours in a dark place. At the 
^1 of ibis time the chlorine has combined 
with the mercury and the cyanogen. Hie 
ddorocyanic add (chhride cyamem* of Ber- 
aetius) 18 gaseous, and occupies the place 
of thecblorineb Tlie matnss must be next 
artificially cooled to 0^ F., at which tem- 
perature the gaseous acid is condensed into 
a soJid. The matrass must now be filled 
with mercury cooled below zero of Fahren- 
heit; a cock is to be fitted to its mouth, 
through which a tube passes, ending in ano- 
ths filled with fragments of dried muri- 
ate of limei Through this the gas must 
pass in leaving the matrass. He mercury 
auat now be slightly heated; the chloro- 
cyanic acid resumes the gaseous state, and 
may then be collected over the pneumatic 
shdf. The use of the cold mercury is to 
cxpd the atmospheric air, and the residuum 
of chknine. At 0° F. it crystallizes in long 
prianwtic needles, which have no smell, or 
at least a very slight one. At 5^ F. it 
mdls into a tiquid ; and at H^' F. it boils. 
At 68^ F. it requires a prosure of four at- 
mospheres for its condensation into a liquid, 
which is colouriess and transparent 

Water absorbs 25 times its bulk of chlo. 
locyanic acid gas, and gives it out in ebuUi- 
tioo, without any change in its nature. Hie 
solution docs not redden litmus, nor does it 
peedpitate the salts of nlver. It may be 
pKsorved a long time without decomposition. 
Alcohol absorbs 100, and ether 50 times its 
volume of this acid gas^ The salifiable bases 
decompose it, and destroy the cyanogen. 

This g^ gives a green colour to the salts 
of iron. To produce this phenomenon, 
ddotocyanlc add must be introduced into a 
solution of a salt of iron, and then a little 
fiee alkali must be added. Cblorocyanic 
add is composed of 57.29 chlorine, and 
4&71 cyanogen, or a volume of each, as 
originally demonstrated by Gay Lussac. 

When, in preparing the cblorocyanic acid, 
the matrf— is exposed to the sunbeam, a 
combination is produced somewhat different 
from the preceding. It is not gaseous, but 
oleaginous, yellow, and dense. It is inso- 
luble in water, but soluble in alcohol. Its 
nature is not well understood ; but it proba- 
bly consists of a combination of cyanogen, 
with more chlorine than exists in the cbloro- 
cyanic 9aA» 

ACID (PERCHLOROCYANIC), or 
Pcrchloride of Cyanogen, has been lately dis- 
covered by Serullas. To obtain it, he takes 
a bottle of the capadty of liiUy two pints 
(imperial) ; introduces into it very dry chlo- 
rine gas, tUi the atmospheric air be expelled ; 
then he putt in fifteen grains of anhydrous 
h|drocyanic add. I( is now corki^ and 



exposed for some days to the sunbeams. 
The chlorine gas is converted* into muriatic 
add, and the perchloride of cyanogen crys- 
tallises on the inner surface of the glass. 
Too much hydrocyanic add produces a mass 
of a deep red colour, similar to taHow in 
consistence^ which a laiger quantity of chlo- 
rine converts into the perchloride. The 
muriatic gas may be expelled ftom the bot- 
tle, by blowing in dry air ; a little water is 
then dropped in, and some fragments of 
glass, by means of which the perdiloride is 
detached. When the substance is taken 
out, it must be dried and distilled. It forma 
now white crystalline needles. Its odour 
u acrid, resembling somewhat the smdi of 
mice; and itt taste is slight Its density is 
1.32. It fuses at 284° F., and sublimes at 
374<> F. Pardly soluble in cold water, it 
is decomposed in boiling water. Ether and 
alcohol dissolve it, and water precipitates it 
from these solutions. . It consists of 72.85 
parts of chlorine, and 27.15 cyanogen, of 
2 volumes of the first, and I of the second. 

ACID (FERROCYANIC). Into a so- 
lution of the amber-coloured crystals, usually 
called pruasiate of potash, pour hydrosulphu- 
ret of baryta, as long as any precipitate falls* 
Throw the whole on a filter, and wash the 
predpitate with cold water. Dry it; and 
having dissoWed 100 parte in cold water, add 
gradually 30 of concentrated sulphuric add ; 
agitate the mixture^ and set it aside to repose. 
The supernatant liquid is the ferroprussic 
add of M. PorreU. 

It has a pale lemon-yellow colour, but no 
smelL Heat and light decompose it Hydro- 
cyanic add is then formed, and white forro- 
cyanate of iron, which soon becomes blue. 
Itt affinity for the bases enables it to displace 
acetic acid, without heat, from the acetates, 
and to form ferrocyanates. 

When a saline solution contains a base with 
which the ferrocyanic acid forms an insolu- 
ble compound, then, ag^reeably to BerthoUet*s 
prindple, it is capable of supplanting its add. 
When ferrocyanate of soda is exposed to vol- 
taic electrici^, the add is evolved at the posi- 
tive pole^ with ito constituent iron. M* Por- 
rett considers this add ** as a compound of 
4 atoms carbon =s 30.00 
I atom azote = 17.50 
I atom iron = 17.50 
1 atom hydrogen ss 1.25 

66.25" 
This sum represents the wdgbt of its prime 
equivalent Ferrocyanate of potash, and of 
baryta, will each therefore^ according to him, 
consist of an atom of add -|- an atom of 
base -|* two atoms of water. 

Berzelius has shown, that when sulpfauret-' 
ted hydrogen gas is transmitted over efflo- 
resced ferruginous pruasiate of potash, heated 
in a glass tube by a spirit lamp, no hydro* 

D 



ACID SO FERROCTANIC. 

cpadc add ot water i» produced; and tliat vmmoDiBaiidfaydrocfanato of ammonia. Tbk 

thereforje tba iron present in the salt is in the production of ammonia in this experiment 

roetallio-state. . On igniting dry ferrooyanate proves, that what remaina after the bydio- 

of potash along with peroxide of copper in a cyanic add which is first erolved^ is a hydro* 

glap9 tube, the same chemist found that the C3ranate, and not a cyanide^ because in the 

gaseous producta consisted of carbonic acid latter case it could only have given hydro- 

and azote, in the proportion of three volumes cyanic add and azotic gas. This substance 

of the former to two volumes of the latter* may be kept without alteration in well cloaed 

The same result wa» obtained from ferro- vessels; but in the air it gradually decom- 

cyanate of baryta. But as the potash and poses, becomes at first greenish, afterwarda 

baryta of the above salts retain a portion of blue, and finishes by bang entirely converted 

the carbonic add, Berzelius next analyzed in into prussian blue. 

^e same way ferrocyanate of lead : he fi^und On the relations of hydrocyanic add and 
that the gas collected towards the end of the iron, the following observations by M. Vau- 
operation, which was quite free from atmoa* qudin are curious. Hydrocyanic add diluted 
pheric air, was a mixture of two parts of car- with water, when placed in contact with iron 
bonic add, and one part of azote by volume, in a glass vessel standing over mercury, quick- 
Hence the carbon and azote in these salts ly produces prussian blue, while, at the same 
exist in the same proportions a» ia cyanogen : time, hydrogen gas is given out. The greatest 
no water was produced. He finally con- part of the prussian blue formed in that 
dudes, that the dry farrocyanates are com- operation, remains in solution in- the liquid, 
posed of one atom of cyanide of iron and It appears cmly when the liquid comes in ooori 
two atoms of cyanide of the odier metal, tact with the air. This shows us that proa* 
potassium, barium, or lead ; according as it sian blue, at a minimum of oxidizement, ia 
is a ferrocyanate of potash, baryta, -or lead, soluble in hydrocyanic add. Dry hydlo* 
that is in question. Berzdius considers the cyanic add placed in contact with iron- fii- 
ferrocyanic or femiretted chyazic add of M. ings, undergoes no change in its colour nov 
Porrett as a super-hydrocyanateof ironinan smell; but the iron, which becomes agglu- 
impure state. To obtain it pure, he adopted tinated together at die ^bottom of the vessel^ 
the following method:— be decomposed well assumes a brown colour. After some diqr8»' 
washed ferrocyanate of lead, under water, by the hydrocyanic acid being separated from 
a current of sulpfaui etted hydrogen gas, re- the iron, and put in a small capsule under s 
moving the excess of sulphuretted hydrogen glass jar, evaporated without leaving any le* 
with a small quantity of ferrocyanate of Irad. sidue. Hierefore it had dissolved no iron* 
The filtered fluid remained limpid and co- Hydrocyanic add dissolved in water, placed 
kwrless in vacuo, leaving eventually a milk- in contact with hydrate of iron, obtsined by 
white substance^ which had no appearance ijf means of potash, and washed with boiling 
crystallization. This white matter has the water, furnished prussian blue immediately^ 
fiiUowing properties :— It dissolves in water, without the addition of any add. Scheele 
to which it imparta an add and agreeable has made mention of this fact. AVhen hydro- 
flavour, but which is rather astringent. In cyanic add is in excess on the oxide of iron^ 
contact with the air it deposits prussian blue, the liquor which floats over the prussian blue 
and assumes a greenish colour. It is in^ assumes, after some time, a beautiful purple 
odorous, unless it has begun to decompose, colour. The liquor, when evaporated, leavea 
When boiled* the liquid gives out hydro- upon the edge of the dish circles of blue, and 
cyanic add, and deposits a powder which be- othen of a purple oolour, and likewise crya- 
comes blue in contact with the air. It is tals of this last colour. When water is poured 
necessary to boil it for some time to decom- upon these substances, the purple-coloured 
pose it entirely. If cold water be saturated body alone dissolves, and gives the liquid a 
with dry super-hydrocyanate, and the solo- fine purple colour. The substance which 
tion be su£^red to remain, it gives small remains undissolved is prussian blue, wbidi 
transparent colourless crystals, which appear has been held in solution in the hydrocyanic' 
to contain water of ciystallization. The add. Some drops of chlorine let fall into 
crystals are apparently quadrilateral prisms this liquid change it to blue, and a greater 
in groups composed of concentric rays. Ber- quantity destroys its colour entirely. It ia 
zelius supposes these to be hydrocyanate, in remarkable, that potash poured into the liquid 
which water replaces the second base that thus deprived of its colour, occasions no pre- 
existed with tlie protoxide of iron. The dpitate whatever. 

white subsUnce obtained by evaporation in Chemists will not fail to remark ftom these 
vacuo does not appear to contain any water, experiments, that hydrocyanic acid does not- 
or rather appears to be the super-hydro- form prussian blue directly with iron ; but' 
cyanate of protoxide of iron, without water that, on the addition of water, (drcumstancea 
of crystallization ; for if it be distilled in a remaining the same), prussian blue is pro- 
small and proper iq>paratus, it gives at first duced. They will remark, likewise^ that 
hydrocyanic add; afterwards cari>onate of cyanogen united to water dissolves iron. 



ACID .51 FERROCYANIC. 

Tfaii « eonfinncd by the iiky tnle wfaidi h from blue to brown. Filter the hipadi' sa- 
bj the diMippeerBnce of its odour, turate the slight alkaline excess with aoetifc 



and by the residue which it leaves when eva- acid, concentrate by evaporation, and allow 
~; yet prunian blue is not farmed, it slowly to cool. Quadrangular bevelled 



Tbew experiments aeem to show that pnissian crystals of the ferropniaaiate of potash will 

^falne is m hydrocyanate^ and not a cyanide. form. 

Tlie ammonia, and hydrocyanic add, dis- Hiis salt is transparent, and of aHieautiful 

•engaged during the whole duration of the lemon or topax-yellow. Its specific gravity 



of Prussian blue^ give a new sup- is 1.890. It has a saline^ cooling, but not 
•port to tfae opinion that this substance is a unpleasant taste. In large crystals it pos- 
hydimcya nate of iron ; and likewise the results seases a certain kind of toughness, and, in 
wUcfa -are fntnished by the decomposition of thin scales, of elasdcity. Hie' inclination of 
pnissian blue by heat in a retort, show clear- the bevelled side to the plane of the crystal 
ly that it contains both oxygen and hydrogen, is about 135^. It loses about 13 per cent 
wfascfa are most abundant towards the end, of water,, when moderately heated; and then 
long after any particles of adhering water appears of a white colour, as happens to the 
•most have been disapatpd. green copperas ; but it does not melt like 

Such oompoands we shall call ferrocya- this salt The crystals retain their figure 
nates. M. Vauquelin and M.Thenanl styled till the beat verges on ignition. At a red 

tfaem ferruginous pruasiates. heat it blackens, but, from the mode of its 

Ferroej^nate of fUuk. Into an egg- formation, we see that even that temperature 
ahaped iron pot, brought to moderate igni- is compatible with the existence of the acid, 

.tion, project a mixture of good pearl-ash and provided it be not too long continued. Wa- 

diy animal matters, of winch hoofs and horns ter at 60^ dissolves nearly one-third of its 

are bcsty in the proportion of two parts of the weight of the crystals; and at the boiling 

Ibnocr to five of the latter. Stir them well point almost its own weight. It is not solu- 

widi m flat iron paddle. The mixture^ as it ble in alcohol ; and hence chemical oompfl- 

calcines, will gradually assume a pasty forai, ers, with needless soiipulosity, have assigned 

•duiiDg which transition it must be tossed to that liquid the hereditary sinecure of 

sbout with much manual labour and dexte- screening the salt from the imaginary dan- 

niy. When the conversion into a chemical ger of atmoqiherical action. It is not altered 

.ooBspomid is seen to be completed by the by the air. Exposed in a retort to a strong 

rrsisfinn of the fetid animal vapours, remove red heat, it yields prussic acid, ammonia, 

xbe pasty mass with an iron ladle. carbonic acid, and a coaly residue, consist- 

If this be thrown, while hot, into water, ing of charcoal, metallic iron, and potash. 

jHime of the prussic add will be converted When dilute sulphuric or muriatic acid is 

.into ammonia, and of course the usual pro- boiled on it, prussic add is evolved, snd a 

duct diminisbed. Allow it to cool, dissolve very abundant white predpitate of proto- 

' it in water, darify the solution by filtration prussiate of iron and potash falls, which af- 

jor subsidenoe^ evaporate, and, on cooling, terwards, treated with liquid chlorine^, yields 

yellow crystals of the ferroprussiate of potash a prossian blue, equivalent to fully one^inji 

vriU form. Separate these, redissolve them of the salt employed. Ndther sulphuretted 

in bot water, and by allowing the solution to hydrogen, the bydrosulphurets, nor infusion 

«Qol very slowly, larger and very regular of galls, produce any change on this salt. 

jcryatak may be had. This salt is now manu^ Red oxide of mercury acts powerfully on its 

fwtiir ed in several parts of Great Britain, on solution at a moderate beat. Prussiate of 

the btfge scale; and therefore the experimen- mercury is formed, which remains in solu- 

tal chemist need not incur the trouble and tion ; while peroxide of iron and metsUic 

Buisaoce of its preparation. Nothing can mercury predpitate. Thus we see that a 

cirrcd in beauty, purity, and perfection, the portion of the mercurial oxide is reduced| 

iijUalii of it prepared at Campsie^ by Mr to carry the iron to the maximum of oxidixe- 

Hadntosh. ment. 

An extemporaneous feiropruasiate of pot- The solution of ferroprussiate of potash is 

ash may at any time be made, by acting on not affected by alkalis ; but it is decomposed 



Prussian blue with pure carbonate of potash, by almost all the salts of the permanent 

prepared from the ignited bicarbonate or bi- metals. Tlie following table presents a view 

tartrate. The blue should be previously di- of the colours of the metallic predpitates thus 

gested at a moderate heat, for an hour or two» obtained. 

in its own weight of sulphuric add, diluted 

with ^we times its weight of water; then fil- Solutions of Give a 

tared, and tfaor6ugbly edulcorated by hot Manganese, White predpitate. 

water from the sulphuric add. Of this pu- Protoxide of iron, Copious white. 

rifled Prussian blue, add successive portions Deutoxide of iron, Copious clear blue. 

to tfae alkaline solution, as long as its colour Tritoxide of iron, Copious dark blue. 

is destroyed, or while it continues to change Tin, White. 



ACID 



52 



FERROCYANIC 



Soliitidns of 


OiYea 


Zinc, 


White. 


Antimony, 


White. 


Uruiiuni^ 


Blood-coloured. 


Cerium, 


White. 


Cobalt, 


Gras»-green. 


Titanium, 


Green. 


Bismuth, 


White. 



1 atom 



Protoxide of copper, White. 

Deutoxide of copper, Crimson-brown. 

Nickely Apple-green. 

Lead, White. 

Deutoxide of mercury. White. 

Silver, White, passing to blue 

in the air. 
Palladium, Olive. 

Rhodium, Platinum, 
and Gold, None. 

If some of these precipitates, for example 
thoae of manganese or copper, be digested in 
a solution of potash, we obtain a ferrocya- 
nate of potash and iron, exactly similar to 
what is formed by the action of the alkaline 
solution on prussian blue. These precipi- 
tates, therefore, contain a quantity of iron. 

The researches of Berselius have shewn 
that dry ferrocyanate of potash is truly a 
compound of one atom of cyanide of iron, 
with two atoms of cyanide of potassium. Its 
compooition may therefore be stated as fol- 
lows: 

With water of crystal. 
CIron = 3.50 15.05 iai5 
I Cyanogen== ^25 } a, qm gg^go 
„ , 5 Cyanogens 6.50 J *^-^ '***•''* 
• •"^"** I Potassiums 10.00 43.00 37.56 

Wate r 12.67 

2a25 100.00 

In its crystallized state it contains three 
atoms of water, which makes its prime equi- 
valent in that case 23.25-f a375sr 26.625. 
To convert this weight into ferrocyanate of 
lead, two atoms of nitrate of lead will be re- 
quired = 41.5 ; so that one atom of nitrate of 

lead = 20.75, will be equivalent to ^^'^^as 

1 3. 3 1 25 of crystals of ferrocyanate of potash. 
Iliese 1 a 31 25 parts of salt, by the action of 
hitrate of lead, afibrd 12.75 parts of nitre, 
whidi contain six of potash. 

Red/errocj/anate of' potash. M. Girardin 
obtained this compound by passing chlorine 
gas into a moderately strong solution of the 
common ferrocyanate of potash, which is to 
be continued until the solution ceases to pro- 
duce any effect when added to a solution of 
peroxide of iron. The liquor is then to be 
concentrated to two-thirds of its volume, and 
set aside in a moderately warm stove to crys- 
tallize: after some time, yellow, brilliant, 
and slender crystals are obtained in form of 
roses ; by a second crystaUization, very long 
needle-form crystals are procured in tufts. 



ThcM crystals are niby-coloured» tnmspA- 
lent, and very brilliant ; tlieir form appears 
to be elongated octahedrons. 

The principal character of this salt is that 
of indicating the proto-aalts of iron, precipi- 
tating them blue or green, according to the 
proportion in solution ; and, on the contrary, 
not precipitating the per-aalts of iron. Una 
re^;ent, according to M. Girardin, is much 
more sensible than the common ferrocy»- 
nate of potash, for it is capable of detecting 
one 90,000dth of protoxide of iron, whUe 
the latter salt does not detect less than ooo 
ISOOdth of the protoxide. 

The red ferrocyanate is soluble in twice ila 
weight of cold water, and less than its own 
weight of boiling water. It is insoluble in 
alcohol, does not act on litmus, but renders 
syrup of violets green. A very small qiiai»- 
tity renders a considerable portion of water 
green. In the formation of this sa)t, half of 
the add of the ferrocyanate is destroyed 1^ 
the chlorine, and the alkali of this half gets 
combined with muriatic acid: the feno- 
cyanates of soda, ammonia, baryta, and Ume, 
are all converted into red ferrocyanatea bj 
chlorine. 

The red ferrocyanate of potash precipitates 
tin white; silver and zinc of an orange co- 
lour ; nickel, bismuth, and titanium, brown ; 
copper, dirty brown ; cobalt and uranium, dif- 
ferent shades of reddish-brown ; both oxidea 
of mercury, brown ; lead is not precipitated^ 
but aiW some time reddisb-brown crystals 
are deposited, which, when decomposed by 
sulphuric acid, separate jier-fimcyanic act^ 
which crystallizes in needles, reddens litmus 
paper, and has a taste at first add, then s^p. 
tic When slightly heated, it molves itself 
into hydrocyanic add and prussian blua 
Bentman*t lUpertoiredeChimief Aug. 1828. 

Ferroc^ntUe of toda may be prepared 
from Prussian blue and pure soda, by a simi* 
lar process to that prescribed for the preced* 
ing salt. It crystallizes in four-sided prisms, 
terminated by dihedral summits. They are 
yellow, transparent, have a bitter taste, and 
effloresce^ losing in a vrarm atmosphere 37( 
per cent. At 55° they are soluble in 4( parta 
of water, and in a much less quanuty of boil- 
ing water. As the solution cools, the crystals 
separate. Thdr specific gravity is 1.458L 
They are said by- Dr John to be soluble in 
alcohol. 

Its constituents are as follows: 

Uron ss a50 11.48 



1 atom 

^ •**""* i Sodium = 6.00 
10 atoms Water 11.25 



I Cyanogen as a25 ) „, ^ 
J Cyanogen a= 6.50 J ^''"^^ 



19.67 
36.88 



30.50 100.00 
Ftrrocyanate of lime may be easily formed 
from prussian blue and lime water. Its solu- 
tion yields crystalline grains by evaporation. 



ACID 53 FERROCYANIC. 

Iron, a500 . * 9.09 

Cyanogen, 9.750 . . 2&80 

Barium, 17.500 .. 48.11 

Water, 5.625 . « 15.47 



Jt coPMata Of' '' 




1 


Iron* 


a50 


11.86 


Cy^nogeOf 


9.75 


3a05 


Caldum, 


5.00 


16.96 


Watefsr 

■ 


11.25 


3a 13 



3&375 100.00 

29.50 100.00 Ferrocyanate of Urontia and tnagnesia huf^ 

The preceding remits, as also those of idso been made. 

Benelius on the fer roc y anide of lead, being JFerrocyanide of lead is fonned by pouring 

apparently discordant with those which I have neutral nitrate of lead into a solution of fer- 

■biled in my paper on the ultimate analysis rocyanate of potash, taking care that the 

flf oiganic compounds (Phil. TVans. 1822), latter be in excess, in order to prevent the 

a few words of explanation seem requi- precipitation of nitrate of lead, which mixes 

sheu I found that an atom of nitrate of with all the insoluble salts with base of oxide 

kadss 20.75, was, by the method of double of lead, if there be an excess of nitrate of 

deoompoaition, equivident to la 1 25 of crys- lead in the liquid from which they are depo- 

tallized ferrocyanide of potassium ; whence I sited. The Uquid remains perfectly neutral. 

infeiTed that this was its atomic weight The precipitate is white with a cast of yellow* 

According to Benefius, 20.75 parts of nitrate Its composition is as follows :— 

9i ioA are eqoiyalent to ia3175 of the Iron, a50 . . a92 

cvyslalliaed ferrocyanide of potassium. This Cyanogen, 9.75 • . 24i.84 

differenoe, though small, would have excited Lead, 26.00 * . 66.24 

ny surprise^ considering the pains that I took, ■ «-_ 

bad not Benelius shewn that ferrocyanide of . 39. 25 100.00 

lead h apt to carry down, in its precipitation. In its state of ordinary dryness it contains 

H portion of nitrate of that metal, to which three atoms of water. 

drcmnstanoe I ascribed the above discrepancy. FerrocyaruUe of iron. We have already 

By my experim'eniB, la 31 75 grains of the described the method of making the ferro- 

cryslalliaed fenoprussiate of potash afford cyanate of potash, which is the first step in' 

a9 of potash, a result not wide of the truth, the manufiicture of this beautiful pigment 

From 21 grains of ferrocyanide of lead I This is usually made by mixing together one 

obtained 2L625 grains of peroxide of iron, part of the ferrocyanate of potash, one part 

=s 1.8375 of metallic iron, while, by Berse- of copperas, and four parts of alum, each pre< 

lius, tibe quantity of iron present is 1.87, a viously dissolved in water. Pkrussian blue, 

dilference only in the second place of ded- mixed with more or less alumina, precipitates* 

mala. But with regard to my products in ItisafWrwardsdriedonchalkstonesinastove, 

the igneous decomposition by peroxide of cop- Pure prussian blue is best prepared by 

per, I am satisfied that a portion of the azote dropping a solution of ferrocyanate of iron 

combined with the oxygen of the peroxide into a solution of red muriate of iron, to 

intD A liqnid compound, whence the gaseous which a slight excess of acid is previously 

Analysis was vitiated. 20.75 parts of nitrate added. The precipitate must be thoroughly 

of lead, containing 14 of oxide, or 13 of me- washed and dried. It retains hygrometric 

taly should yield by Berselius 19.625 of fer- moisture so strongly, that sulphuric acid in 

locyanide of lead; but 1 obtained 21, no vacuo does not detach it 

(doobc, in consequence of some nitrate falling Berzelius found that a portion of very dry 

down along with it . prussian blue, when lighted at the edge, con- 

From la 125 grains of ferrocyankte of tinned to burn by itself like anuuhu, giving 

potash I obtained 1.69 of water, which is a vapour which condensed on a funnel in.* 

12.87 per cent Benelius obtained from verted over it : it was carbonate of ammonia. 

18.4 to 12.9, his calculated atomic propor- One hundred parts of such prussian blue left 

lioo being 12.67. Had it occurred to me a residuum of 60.14 parts of red oxide of 

to double the above product 1.69, then the iron, containing no potash. 

nmnber a38^ being as neariy as possible 3 When a solution of protoxide of iron is pre- 

atoma of water ^ a 375, would have un- cipitated by cyanide of iron and potassium, • 

ravdled all the intricacy, and have satisfied a white insoluble compound is formed, which 

me that the complex constituticm assigned contains potash, and which, by absorbing ox- 

by Berselius waa the true one, since it gave ygen, becomes blue. But it is well known, 

the fewest integer atoms of the constituents, thist a salt with base of protoxide, which 

Ferrocyanate of baryta may be formed in absorbs oxygen without there being an in- 

tiie same way aa the preceding species. Its crease of add, combines with an excess of 

crystak are rhomboidal prisms, of a yellow base. Prussian blue, therefore, which is 

colour, and soluble in 2000 parts of cold prepared by oxidation of the white precipi- 

water and 100 of boiling water. tate, cannot be a neutral compound. Fhis- 

Aocording to Benelius, ferrocyanate of sianblue, thus prepared, has properties which 

baryta oopisista of :«• it does not possess when diflTerently prepared. 



ACID 54 SULPHOCtANIC 

It is soluble in pure water, but not in water dition of sulpburic add. Continiietheboifing 

which contains a certain quantity of any for a little, and when it cools add a little per- 

neutral salt. Thus there are etidently two oxide of manganese in fine powder, which 

blue combinations :*— The one composed of will give the liquid a fine crimson colour. 

3 atoms of hydrocyanate of plotoxide, and 4 To the filtered liquid add a sohition contain- 

atomsof hydrocyanate of deutoxide, in which ing persulphate of copper and protosulphate 

the add and oxygen of the second part is of iron, in the proportion of two of the former 

double that of the first; and another, app»- salt to three of the latter, until the crimson 

rently composed of 1 atom of hydrocyanate tolour disappears. Sulphurocyanide of oop^ 

of protoxide, and 8 atoms of hydrocyanate per falls. Boil this with a solution of potash, 

of deutoxide. which will separate the copper. Distil tfae 

Pure Prussian blue is a mass of an ex- liquid mixed with sulphuric add in a glass 

tremely deep blue colour, insipid, inodorous, retort, and the peculiar add will come over, 

and considerably denser than water. Ndther By saturation wiUi carbonate of baryta, and 

water nor alcohol has any action on it BoiU then throwing down this by the equivalent 

ing solutions of potash, soda, lime, baryta, quantity of sulphuric add^ the sulphurtM 

and strontia, decompose it; forming on one prussic add is obtained pure, 

hand soluble ferrocyanates with these bases, It is a transparent and colourless liquid, 

and on the other a residue of brown peroxide possessing a strong odour, somewhat resenw- 

of iron, and a yellowish-brown sub-ferrocya- bling acetic add. Its spedfic gravity is only 

nate of iron. This last, by means of sul- 1.022. It dissolves a little sulphur at a boil- 

phuric, nitric, or muriatic adds, is brought ing heat It then blackens nitrate of silver; 

back to the state of a ferrocyanate, by ab- but the pure add throws down the silver 

Btracting the excess of iron oxide. Aqueous white. By repeated distillations sulphur is 

dilorine changes the blue to a green in a few separated and the acid is decomposed. M. 

minutes, if the blue be recently predfHtated. Porrett, in die Annals of Phil, for May 1819| 

Aqueous sulphuretted hydrogen reduces the states the tomposition of this add, as it exists 

blue ferrocyanate to the white proto-ferro- in the sulphuretted chyazateof copper, to be^ 

^f*"**©* .. . 2 atoms sulphur =4.000 
Its igneous decompodtion in a retort was g carbon :^ 1.509 
executed by M. Vauquelin with minute at- [ azote := 1.754 
tention. He regards it as a hydrocyanate, i hydrogen =:0!l32 
or mere cyanide of iron ; but the changes he 'TuQA, 
describes are very complex. The general re- 
sults of M. Vauquelin's analysis were hydro- This is evidently an atom of the hydrocyj> 
cyanic add, hydrocyanate of ammonia, an oil anic acid of M. Gay Lussac, combined with 
soluble in potash, crystalline needles, which 2 of sulphur. If to the above we add 9 for 
contained no hydrocyanic add, but were an atom of protoxide of copper, we have 
merely carbonate of ammonia ; and finally, 16.394 for the prime equivalent of the me- 
a ferreous residue slightly attracted by the talUc salt. When cyanogen and sulphuret- 
magnet, and contaming a little undecomposed ted hydrogen were mixed together by M. Gay 
prusdan blue. Lussac in his researches on the prussic piin- 

IVoust, in the Annates de Chimie, voL Ix. ciple, he found them to condense into yellow 

states, that 100 parts of prussian blue, with- adcular crystals. M. Porrett has since r^ 

out afum, yield 0.55 of red oxide of iron by marked, that these crystals are not formed 

combustion ; and by nitric add, 0.54. 100 when the two gases are quite dry, but that 

of cyanate of potash and iron, he further they are quickly produced if a drop of water 

says, afford, after digestion with sulphuric or is passed up into the mixture. He does nok 

nitric add, 35 parts of prussian blue. think thdr solution in water corresponds to 

Ferrocyanate of ammonia is best prepared liquid sulphuretted chyazic add : it does not 

by acting on ferrocyanate of lead with caus- change the colour of litmus ; it has no effect 

tic ammonia. Hie solution being evaporated on solutions of iron ; it contains neither prus- 

in vacuo, a pulverulent salt is obtained. It sic nor sulphuretted chyazic add; yet this 

is a hydrocyanate of protoxide of iron, com- add is formed in it when it is mixed first with 

bined with hydrocyanate of ammonia. an alkali and then widi an add. The same 

ACID (SULPHOCYANIC). The sul- treatment does not form any prussic add. 

phuretted chyazic add of M. Porrett M. Gay Lussac states, that the yellow 

Dissolve In water one part of sulphuret of needles obtained from the joint action of 

potash, and boil it for a considerable time ^anogen and sulphuretted hydrogen, are 

with three or four parts of powdered prussian ** composed of 1 volume of cyanogen, and 

blue added at intervals. Sulphuret of iron \\ volumes of sulphuretted hydrogen." 

is formed, and a colourless liquid, containing The sulphocyanate of the red oxide of iron 

the new acid combined with potash, mixed is a deliquescent salt, of a beautiful crimson 

with hyposulphate and sulphate of potash, colour. It may be obtained in a solid form 

Render this liquid sensibly sour, by the ad- by an atmosphere aitificiBlly dried. - "' . 



ACID 



U 



HYDROXANTHIC 



Groltlias and Vogd, bj fustog ni^)hur 
with ftrrocjanate of potish, diasolving, fiU 
tering^ and drfing, obtained a substaaoe which 
Bendius has shown to be a sulphocyaoide of 
potwiiim Though he was not able to se- 
parate the sulphoqranogen or sulphuret of 
cfanqgen from the base, so as to hare it in 
a separate slsle, yet he deduced its compo- 
sitiout from experiments, as being one atom 
of cyam^gen 3LS5» •^ two atoms of sulphur 

Tlie sulphoeyanide of potassium is com- 
posed of potassium one atom 5, 4~ sulpho- 
'cyanojgen one atom 7.25, :s 12.25. 

MM. Tiedmann and Gm^n proved the 
■preaenoe ef sulphocyanide of potassium in 
the saliva of man ; and of sulphocyanide of 
lodiuin in that of the sheep. By distilling 
•human saliva, I have obtained a product <^ 
aulpbocyanic add in the receiver. See 
•Onuif, and Sauva. 

Siilphocyanic add consists of one atom of 
hydrogen 0.125^ 4~ ^"^ ttam of sulpho- 
^cyanogen 7.25, = 7.375^ On substituting 
selenium for sulphur, a selenio-cyanide of 
potassium was formedt perfectly analogous to 
the sulphocyanide. 

IVofesBor Zeise of Copenhagen describes 
(Ann- de Ck.et PkyM. zzvi) a new acid, and 
« new class of salts, produced by mixing in 
« wide-mouthed flask 16 measures of sulphu- 
ret of carbon with 45 measures of alcohol, 
and 100 measures of alcohol saturated with 
•ammoniacal gas, at a temperature of 53^ F. 
•Two sets of cryatak form. The first are 
-finished in an hour or two, and have a feathery 
aspect He considers them to be bydroxan- 
thate of ammonia. The formation of the 
aeoond set of crystals takes 30 or 40 hours. 
'Tlicaeare distinctly grouped in stars, have 
^onsidenble lustre, and a prismatic form. 
•Tbej are hydrosulphuretted hydrosulphocy- 
anate of ammonia. The flask or phial should 
be well closed with a ground stopper during 
the -formation of these crystals, which are 
■usually of a bright yellow colour. The salts 
of peroxide of copper produce, in the solution 
of that salt in water, a yellow flocculent pre- 
dpitate. This seems to be a compound of 
ordinary hydrosulphocyanic add with bisuU 
phurct of copper. On dissolving one part 
of bydroaulphuretted hydrosulpbocyanate of 
nmmonia in about 180 of water, adding sui- 
phuric or muriatic adds diluted with 16 parts 
of water, till there be an add excess, and 
then dropping into this mixture, in succes- 
sive mall portions, a solution of red oxide of 
iron in sulphuric or muriatic arid, the liquid 
becomes a little dark and muddy, but it soon 
brightens up, with the formation in great 
abundance of crystalline white scales, which 
rapidly settle to the bottom. These crystab 
are to be taken out, and dried by pressure 
between folds of filtering paper, lliis nut- 
ter comaina no iron ; bat is i|. peculiar com- 



pound of sulphur, carhon, azote^ and hydro- 
gen, to which M. Zdse gives the name of 
crystalline hydrosulpburet of cyanogen, com- 
posed probably of 1 atom of azote, 2 of car- 
bon, 4 of sulphur, and 2 of hydrc^g^en. Hy- 
drosulphuretted hydrosulpbocyanate of am- 
monia is represented as contsining 1 atom 
ammonia 2.125, 1 hydrosulphocyanic acid 
7.375, and 1 sulphuretted hydrogen 2.125, 
r= 1 1.625. See Acid (Hydroxamthic). 

ACID (HYDROSELENIC). The best 
process which we can employ for procuritkg 
this add, according to M. Berzelius, con- 
sists in treating the seleniuret of iron with 
the liquid muriatic add: (^Ann, de Chim, 
et de Phys. ix. 24a) The add gas evolvM 
must be collected over mercury. As in this 
case a little of another gas, condensible ne- 
ther by water nor alkaline solutions, appears, 
the bat substance for obtaining absolutdy 
pure hydroselenic add would be sdeninret 
of potMuum. 

.Sdeniuretted hydrogen gas is colouriess. 
.It reddens litmus. Its density has not been 
determined by experiment. Its smell re- 
sembles, at first, that of sulphuretted hydro- 
gen gas; but the sensation soon chsinges, 
and another succeeds, which is at once pun- 
gent, astringent, and painful. The eyes 
become almost instantly red and inflamed, 
and the sense of smelling entirely disappears. 
A bubble of the size of a little pea is sufii- 
dent to produce these effects. Of all the 
bodies derived from the inorganic kingdom, 
seleniuretted hydrogen is that which ezerdses 
the strongest action on the animal economy. 
Water dissolves this gas ; but in what pro- 
portions is not known. This solution dis- 
turbs almost all the metallic solutions, pro- 
dudng black or brown predpitates, which 
assume, on rubbing with polished haematites, 
a metallic lustre. Zinc> manganese, and 
4;erium, form exceptions. They yield flesh- 
coloured predpitates, which appear to be 
hydroseleniurets of the oxides, whilst the 
others, for the most part, are merely metallic 
aeleniurets. 

ACID (HYDROXANTHIC). If a 
certain quantity of sulphuret of carbon be 
poured into an alcoholic solution of one of 
the alkalis, a neutral liquid is obtained, in 
consequence of the formation of a new add, 
which neutralizes the alkalL If potash has 
been used, the salt may be obtained dther 
by refrigeration, evaporation, or predpitstton 
by sulphuric ether. It contsins no carbonic 
acid, or sulphuretted hydrogen, but an add 
whidi is in the same relation to sulphuret of 
carbon that hydrocyanic add is to cyanogen. 
Its compounds have been called hydroxan- 
thates. The add may be obtained by pour- 
ing a mixture of four parts of sulphuric add 
and three of water on the salt of potash, and 
in a few seconds adding abundance of water. 
.The add collects at the bottom of the water 



ACID ^ INDIGOIC. 

M a tnnspareiit ilightly coloured dU; i% hydrogen through it, diffused in ci^t or ten 

murt be quickly washed with water untU free times its wei^t of boiUng water, 

from sulphuric acid. This acid reddens This acid, eraporated to the consistence of 

litmus paper powerfuUy. Its odour differe syrup, and left to itself, concretes in hard and 

from that of sulphuret of carbon. Its taste gnnuhu- crystals. It is very soluble in water 

is add and astringent. It bums readily, and in alcohol. Its taste is acid and very 

giving out sulphurous fumes. Dr Zeite ^ styptic. It combines with the alkaline and 

Copenhagen, Journal of Science, xv. 304 earthy bases, forming salts soluble in water 

ACID (HYPONITROUS). See AaD and alcohoL Its combination with baryta is 

(Nitric). ^^ soluble, and crystallizes with difficulty, 

ACID (HYPOPHOSPHORIC). See and mushroom-Uke. Ita combination with 

Acid (Phosphoric). ammonia, when perfectly neutral, does not 

ACID (HYPOPHOSPHOROUS). See form a precipitate with the salta of silver. 

Acid (Phosphorous). mercury, and iron ; but it comports itself 

ACID (HYPOSULPHURIC). See with tiie salts of copper in a peculiar man- 

Acid (Sulphuric). ner, and which seems to characterize the 

ACID (HYPOSULPHUROU&) See acid of str^chnoi, (for the same add is found 

Acid (Sulphurous). in ««» vomica, and in snake-wood, 6ois de 

ACID (IQASURIC). MM. Pelletier couleuvre): this effect consisU in the decom- 

and Caventou, in their elegant researches on position of the salts of copper by its ammo- 

^ihefaba Sancti IgnatU, et nux vomica, having niacal compound. These salts pass imme- 

observed that these substances contained a diately to a green colour, and gradually 

new vegetable base (strychnine) in oombinfr. deposit a greenish-white salt, of very sparing 

lion with an acid, sought to separate the Ut- solubility in water. The acid of strycknoM 

ter, in order to determine its nature. It ap- seems thus to resemble meoonic add ; but it 

peared to them to be new, and they called differs essentially from it, by its action with 

it igasuric add, from the MaUiy name by salts of iron, which imme<hatdy assume a 

which the natives designate in the Indies the very deep red colour with the meconic add ; 

/aba Sancti IgnaliL This bean, according an effect not produced by the acid of HrycH'^ 

to these chemists, is composed of igasurate not. The authon, after all, do not positively 

4>f strychnine, a little wax, a concrete oil, a affirm this acid to be new and peculiar.— 

yellow colouring matter, gum, starch, has- jinn, de Chim, et de Phys, x. 142. 

aonne, and vegetable fibre. ACID (INDIGOIC). . ThU add, first 

To extract the add, the rasped bean must described by Chevreul, is distinct from the 

be heated in ether, in a digester, with a valve carbasotic acid, also pnk^urable from indigo 

of safety. Thus the concrete oil, and a little by the action of nitric add. To obtain Chev- 

i^urate of strydmine, are dissolved out. leul's acid, nitric add sp. gr. 1.285, diluted 

When the powder is no longer acted on by with rather more than ita wdght of water, is 

the ether, they subject it, at several times, to heated in a retort, and small portions of in- 

the action of boiling alcohol, which carries off digo» in fine powder, are added as long as 

Ihe oil which had escaped the ether, as also any sensible effervescence is produced ; a lit- 

ivax, which is deposited on cooling, some tie water being dropped in from time to tune 

igasurate of strychnine^ and colouring mat. to prevent the formation of caibazotic add. 

ter. All the alcoholic decoctions are united, The yellow liquid is separated, while hot, 

filtered, and evaporated. Ihe brownish-yel- from the resinous matter, and by cooling it 

low residuum is diffused in water ; magnesia deposita crystals of the add of indiga This 

is now added, and the whole is boiled toge- was boiled with oxide of lead, filtered, and 

ther (br some minutes. By this means the the salt present decomposed by sulphuric 

igasurate is decomposed, and from this de- add whilst hot; on cooling, the liquor depo- 

composition there resulta free strychnine^ sited the add of indigo in yellowish-white 

and a sub-igasurate of magnesia, very little crystals : these were separated, dissolved in 

soluble in water. Washing with cold water hot water, neutralized by carbonate of b»- 

removes almost completely the colouring ryta, the solution concentrated, and allowed 

matter, and boiling alcohol then separates the to cool ; yellow adcular crystals of a barytic 

strychnine, which falls down as the liquid salt were obtained, which bdng washed with 

cools. Fmally, to procure igasuric add cold water, dissolved in hot water, and de- 

from the sub-igasurate of magnesia, which composed by acids, gave acicukr crystals of 

remains united to a small quantity of colour- the add of indigo, white as snow. OTiey 

log xnatter, we must dissolve the magnedan were collected and washed upon a filter, 

salt in a great body of boiling distilled Tliey shrunk into a small space when dry, 

water; concentrate tlie liquor, and add to it losing almost enUrely thdr crystalline aspect, 

acetate of lead, which immediately throws This add is white, with tlie lustre of sUk; 

down the add in the stete (ff an igasurate of it has a weak add bitter taste, reddens lit- 

lead. ITiis compound is tlien decomposed, mus, dissolves in any quantity in boiling 

by transmitting a current of sulphuretted water or alcohol, forming colourless solu- 



ACID 57 LACTIC. 

iSem, but re y i ir ei 1000 parts of cold water Marceiy known ; that of lima constUutai 7 

to dimlve it. It is volatile; fusing and per oentof ctncAona. 
sutilimiiig witbont decomposition when heat- ACID (KRAMERIC). A peculiar suhi* 

fd in a tube. The fused add, bj cooling, stance^ which M. Peschier of Geneva thou^t 

cr]rstallixes in six-stded plates. In the air it he had found in the root of the JTrameria 

bums with a bright flame^ erolving much irianttria, 

smoke. Nitric add converts it into a car- ACID (LACCIC) of Dr John. Hus 
baaotic add. Ndther chlorine gas, nor chemist made a watery extract of powdered 
aohition of chlorine, has any effect on it It stick lac, and evaporated it to dryness. He 
gives a blood-red colour to solutions of the digested alcohol on this extract, and evapo- 
petozide salts of iron. IVhen decomposed rated the alcoholic extract to dryness. He 
by heat and oxide of copper, it yields aaote digested this mass in ether, and e%-aporated 
and carbonic acid, in the same proportions the ethereal solution ; wlien he obtained a 
as indigo itself. Hie constituents of the syrupy mass of a light yellow colour, which 
add ar«, hydrogen 2, carbon 47, azote 7.3, was again dissolved in alcohol. On add- 
OKygen 43*7, in 100 parts. J 00 parts of the ing water to this solution, a little resin 
aad combine vrith 90 of baryta. fell. A peculiar acid united to potash and 
ACID (lODO-SULPHURIC). When lime remains in the solution, which is ob- 
we poor sulphuric add, drop by drop, into tained free, by forming with acetate of lead 
a ooDcentFBted and hot aqueous solution of an insoluble laccate^ and decomposing this 
iodic acid, there immediately results a pred- vrith the equivalent quantity of sulphuric 
picate of iodo-eulphttric add, possessed of add. Lacdc add crystallizes ; it bas a wine- 
peculiar properties. Exposed gradually tp yellow colour, a sour taste, and is solu- 
Ifae action of a gentle heat, the iodo-sulphu- ble, as we have seen, in water, alcohol, and 
ric add melts, and crystallizes on cooling ether. It precipitates lead and mercury 
into rhomboids of a pale ydlow colour, white; but it does not affect lime, baryta, 
When strongly heated it sublimes, and is or silver, in their solutions. It throws down 
partially decomposed ; the latter portion be- the salta of iron white. With lime, soda, 
ing converted into oxygen, iodine^ and suL* and potssh, it forms deliquescent salts, solu- 
phuric add. ble in alcohol. 

Pfaospboric and nitric adds exhibit similar ACID (LACTIC). The extract which is 
phenomena. These compound adds act with obtained when dried whey is digested with 
great energy on tlie metals. Hiey dissolve alcohol, contains uncombizfed lactic add, lac- 
gold and platinum. tate of potash, muriate of potash, and a 
ACID (IODIC). See p. 40. proper animal matter. As the elimination 
ACID (lODOUS). See p. 4J . of the acid affords an instructive example of 
ACID (KINIC). A peculiar add ex- chemical research, we shall present it at 
tracted by M. Vauquelin Arom dnchona. some detail from the 2d volume of Berze- 
Jjet « watery extract from hot infusions of lius's Animal Chemistry, 
the bark in powder be made. Alcohol re- He mixed the above alcdiolic solution 
moves the resinous part of this extract, and with another portion of alcohol, to which 7V 
kaves a visdd residue, of a brown colour, gf concentrated sulphuric add had been 
which bas hardly any bitter taste, and which luJded, and continued to add fresh portions 
consists of kinate of lime and a mudUiginous gf this mixture as long as any saline pred- 
matter. This residue is dissolved in water, pitate was formed, and until the fluid had 
the Kquor is filtered and left to spontaneous acquired a deddedly add taste. Some sul- 
cvaporation in a warm place. It becomes phate of potash was predpitated, and there 
thick like syrup, and then deposits by degrees lemained in the alcohol, muriadc add, Uedc 
crystalline plates, sometimes hexaedral, so^ie- add, sulphuric add, and a minute portion of 
times rfaomboidal, sometimes square^ and phosphoric add, detached from some bone 
aivrays coloured sKghtly of a reddish-brown, earth which had been held in solution. The 
These plates of kinate of lime must be puri- acid liquor was filtered, and afterwards di- 
fied by a second crystalh'zation. They are then gested with carbonate of lead, which with the 
dissolved in 10 or 12 tunes thdr wdght of Umtic add affords a salt soluble in aloohoL 
water, and very dilute aqueous oxalic add is As soon as the mixture had acquired a sweet- 
poured into the solution, till no more preci- i^h taste^ the three mineral adds bad fallen 
pitate is formed. By filtration the oxaUte down in combination with the lead, and the 
of lime is separated, and the kinic acid bdng lactic add remained behind, imperfectly satu- 
conccntrated by spontaneous evaporation, nted -by a porUon of it, from which it was 
yiekls regular crystals. It is decomposed by detached by means of sulphuretted hydro- 
beat. While it forms a soluble salt with gen, and then evaporated to the consistence 
lime, it does not predpitate lead or sUver of a thick varnish, of a daric brown colour, 
fimn their solutions. These are characters and sharp add taste, but altogether without 
siifiideRtly distiDctive. The ki nates are tmelL 



ACID 



d6 



LITHIC 



In Older to Irae it from tbe ■oimal matter 
which might remain combined with it, ha 
•Mled it with a mixture of a large quantity 
of freah lime and water, so that the animal 
a n hrtan c es were predpitated and deatro y ed 
by the lime. The lime became yellow- 
brown, and die solution almost colourless, 
while the mass emitted a smell of soap lees, 
which disappeared as the boiling was con- 
tinued. The fluid thus obtained was filter- 
cd, and eraporated, until a great part of the 
superfluous lime held in solution was pre- 
cipitated. A smalt portion of it was then 
decomposed by oxalic add, and cartMHiateof 
silver was dissolved in the uncombined lactic 
add, until it was fully saturated. With the 
assistance of the lactate of silver thus obtain- 
ed, a fSuther quantity of muriatic add was 
separated from the lactate of lime, which 
was then decomposed by pure oxalic add, 
free from nitric add* taking care to leave it 
in such a state that neither the oxalic add 
nor lime water afforded a predpitat& It 
was then evaporated to dryness, and disserved 
again in alcohol ; a small portion of oxalate 
ci lime, before retained in union with the 
add, now remaining undissolved. The alco- 
hol was evaporated until the mass was no 
longer fluid while warm ; it became a brown 
clear transparent arid, which was the lactic 
add, tree from all substances that we have 
hitherto had reason to think likely to conta- 
minate It 

The lactic add, thus purified, has a brown- 
yellow colour, and a sharp sour taste, which 
Is much weakened by diluting it with water. 
it ia without smell in the cold, but emits, 
when heated, a sliarp sour smell, not unlike 
that of sublimed oxalic add. It cannot be 
made to crystallise, and does not exhibit the 
slightest appearance of a saline substance, but 
dries into a thick and smooth varnish, which 
plowiy attracts moisture from the air. It is 
very easily soluble in alcohol. Heated in a 
gold spoon over the flame of a candle, it 
first boils, and then its pungent add smell 
becomes very manifest, but extremely dis. 
tinct from that of the acetic add; afteF*> 
wards it is duored, and has an empyreu^ 
matic, but by no means an animal smeU. A 
porous charcoal is left behind, which does 
not readily bum to ashes. When distilled, 
it gives an empyreumatic oil, water, empy- 
reumatic yinegar, cartwnic add, and infl«n- 
mable gases. With alkalis, earths, and me- 
taUic oxides, it affords peculiar salts: and 
these are distinguished by being soluble in 
alcohol, 90i in general by not having the 
least dbpbsition to crystallize, but drying 
into a mass like gum, which slowly becomes 
moist in the air. 

lactate of jtoioMh is obtained, when the 
lactate of lime, purified as haa been men- 
tioned, is mixed with a warm solution of 
carbonate of potash. It forms, in dryings 



a gunimyy light yellow-brown, tnnsparent 
mass, which cannot easily be made hard. 

The iactaie of ioda resembles that of pot- 
ash, and can only be distinguished from it by 
nnalyssi 

LaetaU ofummonku If concentrated lac- 
tic add is saturated with caustic ammonia in 
excess, the mixture acquires a strong volatile 
amell, not unlike that of the acetate or for- 
miate of ammonia, which, however, soon 
ceases. Hie salt which is left has sometimes 
a slight tendency to shoot into crystals. 

liie lactate of baryta may be obtained in 
tlie same way as that ^lime ; but it then con- 
tains an excess of the base. When evaporated 
ft aflbrds a gummy mass, soluble in alcohoL 

The lactate of lime is obtained in the man- 
ner above described. It affivds a gummy 
mass, which is also divided by alcohol into 
two portions. 

Xocfole o^ magnsno, evaporated to the coD- 
sistenoe of a thin syrup, and left In a warm 
plaoe^ shoots into small granular crystals. 

The lactate of wUuer is procured by die- 
solving the carbonate in the lactic add. Hie 
solution is of a light yellow, somewhat inclin- 
ing to green, and has an unpleasant taste of 
•verdigris. 

The latitaU rf iron is of a red-brown co- 
lour, does not crystallise, and is not soluble 
in aloohoL The lactate of tine ciystalliaes. 
Both these metak are dissolved by the lactic 
add, with an extrication of hydrogen gas. 
The lactate of copper, according to its diffe- 
rent degrees of saturation, varies from blue 
to green and dark blue. It does not crys- 
tallize. 

It is only ne cessar y to compare the de- 
scriptions of these salts with what we know 
of the salts which are formed with the same 
bases by other adds, for example^ the acetic, 
the malic, and others, in order to be com- 
pletely convinced that the lactic add must be a 
peculiar add, perfectly distinctfrom all crthera. 
Its prime equivalent may be called 5.8. 

The nanceie add of Braconnot resembles 
the lactic in many respects. 

ACI D (LITHIC). Lithate of potash ia 
obtained by digesting human urinary calculi 
in caustic lixirium; and Fourcroy recom- 
mends the predpitation of the lithic add from 
this solution by acetic add, as a good process 
for obtaining die acid pure, in small, whit^ 
shining, and almost pulverulent needles. 

It has the form of white shining plates, 
which are denser than water. Has no taste 
nor smelL It dissolves in about 1400 parts 
of boiling water. It reddens the infusion of 
litmus. When dissolved in nitric add, and 
evaporated to dryness, it leaves a pink sedi- 
ment. Hie dry add is not acted on nor dis- 
solved by the alkaline carbonates or sub-car- 
bonates. It decomposes soap when assisted 
by heat; as it does also the alkaline ftulr 
pliurets and hydrosulphuret& No add acts 



ACID 



69 



MANGANESIC 



on it, euapt tbow that ocemami its dtioom- 
pcMtkni. It ditsolVcs in hot lolutioiis of 
polnh and soda, and likewiae in ammonia, 
but leas readily. The Uthates may be fbnned, 
citiier by mutually Maturating the two oon» 
■titneiits, or we may diiaoWe the add in an 
ezcev of bate, and we may then precipitate 
by carbonate of anmionia. The lithates are 
aU tasteleas, and resemble in appearance lithic 
add itself. Tbey are not altered by exposure 
to the atmosphere. They are rerj sparingly 
sohible in water. They are decomposed by 
a red heat, which destroys the acid. The 
lithic acid is precipitated from these salts by 
all the adds, except the pniasic and carbonic. 
Ibey are decomposed by the mtrstes, muri- 
ates, and acetates of baryta, stnmtia, lime^ 
magnesia, and alumina. Tbey are predpi* 
tated by all the metallic solutions, except that 
of gold. When lithic add is exposed to heat, 
the prodnclB are carburetted hydrogen, and 
carbonic add, prussic add, carbonate of am- 
monia, a sublimate consisdng of ammonia 
eembined with a peculiar add, which has the 



Its colour is yellow, and it has a cooling 
bitter taste. It dissolves readily in water, 
and in alkaline solutions, from which it is not 
predpttatcd by adds. It dissolves also spar- 
ingly in alcohoL It is volatile^ and when sub* 
limed a second tnne^ becomes much whiter. 
The watery solution reddens vegetable blues, 
but a very small quantity of ammonia de- 
stroys tins piupeity. It does not cause ener- 
vescence with alkaline carbonates. By ev^ 
potation it yields permanent crystals, but ill 
defined, from adhering animal matter. These 
redden vegetsble blues. Potash, when added 
to these crystals, disengages ammonia. When 
tlissolved in nitric add, they do not leave a 
ted stain, as happens with uric add; nor 
docs tiicir solution in water decompose the 
earthy salts, as happens with alkaline lithates 
(or urates). Ndther has it any action on 
the salts of copper, iron, gold, platraum, tin, 
or OBcrcury. With nitrates of silver, and 
mercury, and acetate of lead, it forms a white 
precipitate, soluble in an excess of nitric add. 
Muriatic add occasions no piedpitate in the 
aotntion of these crystals in water. These 
properties show, that the add of the sub- 
liaaate is diflfenent ftom the uric, and from 
every other known add. Dr Austin found, 
that by repeated distillations lithic add was 
resolved into ammonia, nitrogen, and prusdc 
add. See AczB (Pybouthic). 

When lithic add is projected into a flask 
with chlorine^ there is formied, in a little time, 
muriate of ammonia, oxalate of ammonia, 
carbonic arid* muriatic add, and malic acid : 
the same results are obtained by passing 
dilorine through water holding tUs add in 



M. Gay Lussac mixed lithic add with 20 
times its weight of oiide,of copper, put the 



BiixtUFe into a glass tube, and covered it witB 
a quantity of copper filings. Hie copper fil-> 
ings being first healed to a dull red, heat was 
applied to the mixture. Hie gas which came 
over was composed of 0.69 csrbooic add, 
and 0.31 nitrogen. He conceives, that the 
bulk of the carbonic add would have been 
exactly double that of the nitrogen, had it 
not been for the formation of a b'ttle carbo- 
nate of ammonia. Hence, uric acid contains 
two prime equivalents of carbon, and onenf 
nitrogen. This is the same proportion as 
exists in cyanogen. Probably, a prime equi- 
valent of oxygen is present. Dr Prout, in 
the dghth voL of the Med. Chir. Trans, de- 
soibes the result of an analysis of lithic add, 
effected also by ignited oxide of copper, but 
so conducted as to determine the product of 
oxygen and hydrogen. Four grains of lithic 
add yidded, water 1.05, carbonic add 11.0 
c. inches, nitrogen £.5 ditto. Hence^ it con- 
sisted of 

Hydrogen, 2.857 or 1 prime =x 0tl25 
Carbon, Bk286 2 sr 1.509 

Oxygen, 22.657 1 s 1.000 

Nitrogen, 40.00 1 as 1.750 

100.000 4.375 

M. Berard has published an analysis of 

lithic add since Dr Pktmt, in which he also 

employed oxide of copper, 
llie following are the results: 

CartMn, 33.61 ^ Cl Csrbon. 

Oxygen, 18.89f which sp- J 1 Oxygen. * 

Hydrogen, 8t34 ^ proacb to y 4 Hydrogen; 

Nitrogen, 39.163 (.1 Nitrogen. 

loaoo 

Here we find the nitrogen and carbon 
nearly in the same quantity as by Dr Prout; 
but there is much more hydrogen and less 
oxygen. By urste of baryta, we have the 
prime equivalent of uric add equal to 15.67^ 
and by urate of potash it appears to be 14.0. 
It is needless to try to accommodate an ar- 
ladji^ement of prime equivalents to these dis- 
crepandes. . llie lowest number would ro- 
quire, on the Daltonian plan, an association 
of more than twenty atoms, the grouping of 
which is rather a sport of fancy than an exer<- 
dse of reason. For what benefit could ac- 
crue to chemical sdence by stating, that if 
we consider the atom of lithic add to be 
16.75^ then it would probably consist of 

7 atoms Osrbon, s=s 5.25 31.4 

3 Oxygen, S3 3.00 17.90 
12 Hydrogen, ss 1.500 a90 

4 Nitrogen, s=s7.00 41.80 

26 16w75 100.0 

ACID (MANGANESIC). When man- 
ganesate of potash (cameleon mineral) is dis- 
tilled with a little anhydrous sulphuric acid, 
manganesic add is evolved in the form of a 
red transparent gas, which dissolves in water. 



ACID 



00 



MALIC. 



fiimiiiig a nd lolntioii. Tlie gn ftvqiMDtiy 
deoompoMS qmntaneouslj in the retort with 
ezplosioD, produciDg oxide of numganese and 
oxygen. 

Manganeaate of potash was analjaed by 
distilling it with excess of sulphuric add, col- 
lecting the oxygen disengaged, and estimat- 
ing tlM proportion of protoxide of manganese 
and salts <i potssh remaining in the retort. 
According to these experiments^ the 
consists of 

Bfanganese, 58^74 

Oxygen, 41.26 



100.00 




And the manganesate of potash cai 


Idncd— 


Potash, 25.03 


38.75 


Mangsnesic add, 58.44 


67.85 


Water, 81.83 





100.00 



loaoo 



ACID (MALIC). Hie add of apples, 
called malic, may be obtained most conve- 
niently and in grntest purity from the berries 
of the mountsin-ash, called torlnu or pyrus 
aueupariaf and hence it has been called sor- 
bic add. This was supposed to be a new 
and peculiar add by Mr Donovan and M. 
Vauquelin, who wrote full dissertations upon 
it But it now appears that the sorbic and 
pwv malic acids are identical. 

Bruise the ripe berries in a mortar, and 
then squeeze them in a linen bag. Ibey 
yield nearly half their weight of juice, of the 
apecific grsvity of 1.077. This visdd juice, 
by remaining for about a fortnight in a warm 
tampersture, experiences the vinous fermen- 
tation, and would yield a portion of alcohoL 
By tills change^ it has become bright, dear, 
and passes eadly through the filter, while the 
sorbic add itself is not altered. Mix the 
dear juice with filtered solution of acetate of 
lead. Separate the predpitate on a filter, 
and wash it with cold water. A large quan- 
tity of boiling water is then to be poured 
upon the filter, and allowed to drain into 
glass jars. At the end of some hours the 
scdution deposits crystals of great lustre and 
beauty. Wash these with cold water, dis- 
solve them in boiling water, filter, and crys- 
tallise. Collect the new crystals, and boil 
them for half an hour in 8.3 times their 
weight of sulphuric add, spedfic gravity 
1.090, supplying water as fast as it evapo- 
rates, and stirring the mixture diligently with 
a glass rod. 1^ dear liquor is to be de- 
csnted into a tall narrow glass jar, and, while 
still hot, a stream of sulphuretted hydrogen 
is to be passed through it. When the lead 
has been all thrown down in a sulphuret, the 
liquid is to be filtered, and then boiled in an 
open vessel to dissipate the adhering sulphu- 
retted hydrogen. It is now a solution of 
sorbic add. 



When it is ev apu i at e d to the eonsistence 
of a syiup, it forms mammdated nwssei of a 
crystalline structure. It still contains a con- 
siderable quantity of water, and deliqnesoea 
when exposed to the air. Its solution is trans- 
parent, oolourieas, void of smdl, but power- 
fully sdd to the teste. Lime and baryta 
waters are not predpitated by solution of the 
sorbic add, although ihe sorbate of lime is 
nearly insoluble. One of the most charac- 
teristic p roper ti es of this add is the predpi* 
tate which it gives with the acetate of lead, 
which is at first white and flocculent, but 
afterwards assumes a brilliant crystalline ap- 
pearance. With potash, soda, and ammonia* 
it fonns crystsllisable salts contsining an ex- 
cess of acid. Huit of potash is ddiquescent. 
Sorbate of baryta consists, according to M. 
Vauquelin, of 47 sorbic add, and 53 baryta, 
in 100. Sorbate of lime well dried, appewed 
to be composed of 67 add -f- 33 lime =r 100. 
Sorbate of lead, which in solution, like most 
of the other sorbates, retains an adduloua 
tsste, consists in the dried state of 33 add -f« 
67 oxide of lead in 100. The ordinary sor- 
bate contains 18.5 per cent of water. M. 
Vauquelin says that Mr Donovan was mis» 
taken in supposing that he had obtained super 
and sub-eorbates of lead. There is only one 
salt with this base^ according to M. Vau- 
quelin. It is nearly insoluble in cold water ; 
but a little more so in boiling water : as it 
cods, it crystallizes in the beautiful whiter 
brilliant, axid shining needles, of which we 
have already spoken. A remariiable pheno- 
menon occurs when sbrbate of lead is boiled 
in water. Whilst one part of the salt satu- 
rates the water, the other part, for want of a 
Buffident quantity of fluid to dissolve it, is 
partially mdted, and is at first kept on the 
surfiue by the force of ebullition, but after 
some time falls to the bottom, and as it cook 
becomes strongly fixed to the vesseL 

To procure malic add, M, Brseonnot sa- 
turates with chalk the juice of the scsrcdy 
ripe berries, evaporates to the consistence of 
a syrup, removing the froth ; and a granular 
soibate falls, which he decomposes by car- 
bonate of soda. The soibate of soda u fieed 
fiom colouring matter by a little lime^ strsin- 
•ed, freed finom lime by carbonic add ga% and' 
decomposed by subaoetate of lead, and treated 
as above. 

M. Vauquelin analyzed the add in the 
dry malates of copper and lead. 

The following are its constituents: 
Hydrogen, 16.8 
Carbon, 88.3 
Oxygen, 54.9 

100.0 
M. Vauquelin*s analysis of the malate of 
lead gives 7.0 for the prime equivalent of ttus 
acid ; the sorbate of lime gives 7.830 ; and 
.the lorbate of baryta 8.6. 



ACID 



61 



MECONIC. 



The cakmODS salt hsving been procured 
in » neutnl alale* by the addition of carbonate 
of poCnh to iti actduloiis lolution, it mi^t 
nadily be mixed with as much carbonate of 
lime M woold diminiab the apparent equiya- 
lent of «cidilrom 7.50 to 7.290; especiaUj m 
the barytic compound gives no less than 8.6. 
Had the composition of the malate of lime 
been 67.7 and 38.3, instead of 67 and 33» 
the prime equivalent of the add would come 
out 7.S, as its ultimate analysis indicates. 
Dr Ptout's analysis of malic acid gives 

Carbon, 40.68 

Water, 45.76 

Oxygen, 1&56 

loaoo 

As the pure malic add appears to be witb- 
■ont odour, without colour, and of an agree- 
able taste, it might be substituted for the tar- 
taric and dtric, in medidne and the arts. 

The same add may be got from apples, in 
n similar way. 

ACID (MARGARIC). When we im- 
mene soap made of pork-grease and potash 
in a huge quantity of water, one part is dis- 
solved, while another pert is predpitated in 
the form of several brilliant pellets. Hiese 
are separated, dried, washed in a large quan^ 
tity of water, and then dried on a filter. They 
are now dissolved in boiling alcohol, sp. gr. 
€l880^ ftom which, as it cools, the pearly sub- 
stance ftlla down pure. On acting on this 
with dilute muriatic add, a substance of a 
pf<BiKy kind, which M. Chevreul, the.dis- 
ooverer, calls margarine, or margaric aad, is 
flcparsted. It must be well washed with 
water, dissolved in boiling alcohol, from 
which it is recovered in the same crystalline 
pearly form, when the solution cools. 

Margaric add is peariy white, and taste- 
less. Its smdl is feeble^ and a little similar 
to that of mdted wax. Its spedfic grarity is 
inferior to water. It melts at 134^ F. into 
limpid colourless liquid, which ciyfr> 
on cooling, into brilliant needles of 
the finest white. It is insoluble in water, but 
very soluble in alcohol, sp. gr. 0.800. Cold 
margaric add has no acticm on the cokmr of 
litmus; but when heated so as to soften with- 
out melting, the blue was reddened. It com- 
bines with the salifiable bases, and forms nei>> 
tral compounds. 100 parts of it unite to a 
quantity of base containing three parts of 
oxygen, supposing that 100 of potash contain 
17 of oxygen. Two orders of margarates are 
formed, the margarates and the supermarga- 
FBtes; the former bring converted into the 
latter by pouring a large quantity of water 
on them. Other ito betides that of the hog 
yield this substance. 

jidiL Base. 
Mafgante of potash consists of 100 17.77 
fiopermargaratc^ • • 100 8.88 
Margame of soda, - - 100 12.78 



Jcid. Jh$i. 
Baryta, ... 100 88.03 
Strontia, ... 100 80.83 

lime^ - * - . 100 11.06 

Potash. 
Supermargarate of Human fat, 100 a85 

Sheep fat, 100 &68 
Ox fat, 100 &78 

Jaguar fat, 100 a60 
Goose fot, 100 a77 
If we compare the above numbera, we shall 
find 35 to be the prime equivalent of mar- 
garic add. 

Hiat of man is obtained under ^ree dif- 
ferent forms, lu. In very fine long needles, 
disposed in flat stars. 2d, In very fine and 
very short needles, forming waved figures, like 
those of the margaric add of carcasses. 3tf, 
In very large brilliant crystals disposed in 
stars, similar to the margaric add of the hog. 
The margaric adds of man and the hog re- 
semble each other ; as do those of the ox and 
the sheep ; and of the goose and the jaguar. 
The compounds with the bescs are real soape. 
The solution in alcohol afibrds the transpa- 
rent soap of this country.— ^nn. de Chimie 
€t de Phyt, several volume^ 

ACID (MECONIC). This add is a con- 
stituent of opium. It was discovered by M. 
Sertuemer, who procured it in the following 
way :-*After predpitating. the morfthia from 
a solution of opium by ammonia, be added 
to the reridual fluid a solution of the muriate 
of baryta. A predpitate is in this way 
formed, which is supposed to be a quadruple 
compound, of bsjyta, morphia, extract, and 
the meconic acid. Ihe extract is removed 
by alcohol, and the baryta by sulphuric add ; 
when the meconic add is left merely in com- 
bination with a portion of the morphia, and 
from this it is purified by successive solutions 
and evaporations. Hie add, when sublimed, 
forms long colourless needles; it has a strong 
affinity for the oxide of iron, so ss to take it 
from the muriatic solution, and form with it 
a cherry-red precipitate. It forms a crystal- 
lisable salt with lime, which is not decom- 
posed by sulphuric add ; and what is curious, 
it seems to possess no particular power over 
the human body, when recdved into the sto- 
mach. The essential salt of opium, obtained 
in M. Derosne's original experiments, was 
probably the roeconiate of morphia. 

M. Robiquet has made a useful modifica- 
tion of the process for extracting meconic 
acid. He treats the opium with magnesia, 
to separate the morphia, while meconiate of 
magnesia is also formed. Tlie magnesia is 
removed by adding muriate of baryta, and 
the baryta is afterwards leparated by dilute 
sulphuric add. A larger proportion of me- 
conic add is thus obtained. 

M. .Robiquet denies that meconic add 
preripitates iron from the muriate; but, ac- 
cording to M. Vogel, its power of redding 



ACID 62 MELLITIC. 

aollitioiM dC iron is so great, as to render it a - To pracufv meooniate of inorpliia» says 

more delicate test of this metal) than even the Dr Gioseppe Mened, reduce^ood opium to 

lerrocyanate of potasb.^ powder, piii it into a paper filter, iidd dis- 

To obtain puve meoonic acid from the me- tilled water to it, and slightly agitate it. In 

.coniate of baryta, M. Choulaut triturated it this way wash it, till the water passes through 

in a mortar with its own weight of glassy colourless; then pass a little diluted alcohol 

• borscic acid. Hiis mixture being put into a .through it ; dry the insoluble portion (now 
small glass flask, which was sturrounded with diminished to one-half) in a dark place; di^ 

*sand in a sand pot in the usual manner, and .gett it when diy in strong alcohol for a few 

'the red heat being gradually raised, the me- minutes, applying heat ; separate the -solu- 

.conie acid sublimed in the state of fine white tion, which, by cooling and after erapora- 

• scales or plates. It has a strong sour taste, tion, will yield well crystalliaed meooniate €tf 
which leaves behind it an impression of bitter- morf^iia of a pale straw colour. Gionu tU 

-ness. It dissolves readily in water, alcohol, JFittca, viL 2ia 

and ether. It reddens the greater number ACID (MEL ASSIC). The add present 

of v^etable blues, and changes the solutions in melasses, which has been thought a pecit. 

of iron to a cherry-red colour. When these liar add by some^ by others the acetic 

.solutions are heated, the iron is precipitated ACID (MELLITIC). M. Kbqirothdis. 

in the state of protoxide. covered in the melilite^ or honey-stone, what 

The mecoiliiatei examined by Choulaut ara he conceives to be a peculiar add of the vo- 

the following:— getable kind, combmed with alumina. This 

Itt, Meooniate of potash. It crystallixes sidd is easily obtained by redudng the stone 

■in four-sided tables, is soluble in twice its to powder, and boiling it in about 70 times 

•weight of water, and is composed of its weight of water ; when the add will dis- 

Meconicadd, 27 2.7 solve, and may be separated from the ahimina 

Potash, GO 6.0 by filtration. By evaporating the solution. 

Water, 13 it may be obtained in the form of crystals. 

— The following are ita characters:— 

100 It crystallises in fine needles or globules 

It is destroyed by heat by the union of these, or small prisms. Ita 

Sd, Meooniate of soda. It crystallizes in taste is at first a sweetish sour, which leaves 

soft prisms, is soluble in five times its wdght -a bitterness behind. On a pkte of hot metal 

of water, and seems to effloresce^ It is de- it is readily decomposed, and dissipated in 

fltroyed by heat It consists of copious grey fumes, which afiect not tho 

Add, 32 3.2 smell, leaving behind ft small quantity of 

Soda, 40 4.0 ashes, that do not change dther red or blue 

Water, 28 tincture of litmus. Neutralized by potash it 

— — — crystallizes in groups of long fuisms; by 

100 soda, in cubes, or triangular liminse, somo- 

3d, Meooniate of ammonia. It crystallizes times in groups, sometimes single ; and by 

•in star-form needles, which, when sublimed, ammonia, in beautiful prisms with six planes, 

.lose thdr water of crystallization, and as- which soon lose thdr transparency, and ac- 

sume the shape of scales. The crystals ara quire a silvery-white hue. If the mellitic 

soluble in 1^ their weight of water, and are add be dissolved in lime vrater, and a so- 

* ' lution of caldned stronda or baryta be drop- 
ped into it, a white predpitate is thrown 
down, whidi is redissolved on adding mu- 
riatic acid. With a solution of acetate of 

— baryta, it produces likewise a white predpi- 

100 tate^ which nitric add rediasolves. With so- 

if two parts of sal ammoniac be triturated lution of muriate of baryta, it produces no 

irith three parts of meconiate of htsyiB, and predpitate, or even cloud ; but after standing 

heat be applied to the mixture, meconiate of some time, fine transparent needly crystals 

-ammonia sublimes, and muriate of baryta are deposited. Hie mellitic add produces 

remains. i>o duinge in a solution of nitrate of sil- 

4f/k, Meconiate of lime. It oystallizes in ver. From a solution of -nitrate of mer- 

prisms, and is soluble in eight times its weight cury, dther hot or cold, it throws down a 

of water. It consists of copious white predpitate, which an addition 

of nitric add immediately redissolves. With 

nitrate of iron it gives an abundant predpii> 

tate of a dun yellow colour, which may b^ 

redissolved by muriatic acid. With a solu- 

100 tion of acetate of lead, it produces an abun- 

As the potash and lime compounds give dant predpitate, immediately redissolved on 

^yearly the sfane acid ratio, we may take thdr adding nitric add. With acetate of copper, 

mean of it as the true prime =2.8. it gives a greyish-green precipitate; but it 



composed of 






Acid, 


40 


2.03 


Ammonia, 


42 


2.13 


Water, 


18 





Add, 


34 


2.882 


Lime, 


42 


ad60 


Water, 


24 





ACIIX 



es 



MOROXYLIC. 



docs not aifcet a solirtioa of tnuriajtB of cop- 
por. Lime water precipitated by it ii im- 
niadiaieiy rediaeoiYed on adding nitric add. 

Mi Klaprotfa wa^ never able to cooTert 
tliia acid into the oxaKc by means of nitric 
aad» which only changed its brownish ooloar 
to a pale yellow. 

The meUiUf or natiTe mellate of alumina, 
cooeisf, according to Klaproth, of 46 acid -|- 
16 alumina ^ 38 water =s 100 ; from which* 
calling the prime of alumina 2.85» that of 
mellitic acid appean to be 6.6. 

ACID (M£NISP£RMIC). M. Caaa* 
Kca baa published, m the 90th toI. of the 
Ann. de Chim. et de Phys. a Memoir on 
Menispermum Cocculus, in which he de- 
monstrates,— 

I. Thai menispermie add does not exist. 

2> That picrotoxia does not possess alk»- 
fina p roperties, and ought not to be consi- 
dend as a new vegetable saUfiable base, but 
BMfcly as a peculiar bitter principle, as M. 
BouUay announced it in his first paper. 

ACID(MOLYBDIC). The native sul- 
phmwtxif molybdenum bdng roasted for some 
^tmBi and dissolved in water of ammonia, 
when nitric add is added to this solution, the 
molybdic add preripitates in fine white scales, 
which become yellow on melting and sub- 
fiming them. It changes the vegetable blues 
to red, but less readily and powerfully than 
the nurfybdous add. 

' M. Bucbols found, that 100 parts of the 
sulphuret gave 90 parts of molybdic add. 
In frther experiments in which he oxidized 
molybdenum, he found that 100 of the metal 
combined with from 49 to 50 of oxygen. 
Benelius, after some vain attempts to analyxe 
the molybdates of lead and baryta, found . 
ttet the only method of obtsining an exact 
iiesult WW to form a molybdate of lead. He 
dissolved 10 psrts of neutral nitrate of lead 
in water, and poured an excess of solution of 
cTfstalliaed molybdate of ammonia into the 
liqnid. The molybdate of lead, washed, 
dried, and heated to redness, wdghed 1 1.068. 
Ko traces of lead were found in the liquid by 
sulphate of ammonia : hence these 1 1.068 of 
lead, evince 67.3 per cent of oxide of lead. 
Thia salt then is composed of 

Molybdic add, 39. 1 9i 9.0 
Oxide of lead, 60.806 14.0 ' 



100.000 
And from Bucfaolz we infer, that this prime 
c^ivalent 9 consists of 3 of oxygen -|- 6 me- 
tal ; while molybdous add will be 2 oxygen 
4- 6 metal s aO. 

Moljbdic add has a spedfic gravity of 
3b460. In an open vessel it sublimes into 
brilliant yellow sodes ; 960 parts of boiling 
walsr dissolve one of it, aflbrding a pale yel- 
low solution, which reddens litmus, but has 
DO taste. Sulphur, charcoal, and several me- 
tals decompose the molybdic add. Molybdate 



of potMh is a colourless sah. Molybditadd 
gives^ with a nitrate of lead, a white preripii 
tate, soluble in nitric add ; with the nitratei 
of mercury and silver, a Vhite flaky predpi- 
tate ; with nitrate of copper, a greenish- pre- 
cipitate ; with solutions of the neutral ml* 
phate of xinc, muriate of bismuth, muriate of 
antimony, nitrate of nickel, muriates of gold 
and platinum, it produces white predpitates. 
When mdted with borax, it yields a bluish 
colour ; and paper dipped in its solution be- 
comes, in the sun, of a beautiful blue. 

Hie neutral alkaline molybdates predp!:> 
tate aU metallic solutions. Gold, muriate of 
mercury, zinc, and manganese, are predpi- 
tated in the form of a white powder ; iron 
and tin, from thdr solutions in muriatic add, 
of a brown colour ; cobalt, of s rose colour ; 
copper, blue ; and the solutions of alum and 
quicklime, white. If a dilute solution of re- 
cent muriate of tin be predpitsted by a dilute 
solutidn of molybdate of potash, a beautifiil 
blue powder is obtained. 

The coneentrated sulphuric add dissolves 
a considerable quantity of the molybdic add^ 
'the solution becoming of a fine blue colour 
as it cools, at the same time that it thickens : 
the colour disappears again on the application 
of heat, but returns again by cooling. A 
strong heat expels the sulphuric add. The 
nitric add has no effect on it; but the mu- 
riatic dissolves it in considerable quantity, and 
leaves a dark blue residuum when distilled. 
With a strong heat it expels a portion of sul- 
phuric add from sulphate of potash. It also 
disengages the add from nitre and common 
salt by distillation. It has some action upon 
the filings of the metals in the moist way. 

Hie molybdic acid has not yet been em- 
ployed in the arts. 

ACID (MOLYBDOUS). The deut- 
oxide of molybdenum is of a blue colour, and 
possesses acid properties. Triturate 2 parts 
of molybdic add, with 1 part of the metal, 
along with a little hot water, in a porcelain 
mortar, till the mixture assumes a blue co* 
lour. Digest in 10 parts of boiling water, 
filter, and evaporate the liquid in a heat of 
about 120^. The blue oxide separates. It 
reddens vegetable blues, and forms salts with 
the bases. Air or water, when left for some 
time to act on mc^ybdenum, converts it into- 
this acid. It consists of about 100 metal to 
34 oxygen. 

ACID (MORIC). See Acid (Mor- 

OXYUC). 

ACID (MOROXYLIC). In the bo- 
taiuc garden at Palermo, Mr Thomson found ' 
an uncommon saline substance on the trunk 
of a white mulberry tree. It appeared as a 
coating on the surface of the bark, in little 
granulous drops of a yellowish and blackish- 
brown colour, and had likewise penetrated its 
substance. M. Klaproth, who analyzed it, 
found that its taste was somewhat like that of* 



ACII> 



6i 



MURIATIC 



tuccinic add; on burning cods it swelled 
up a little, emitted a pungent Tapour acarcel j 
▼isible to the eye, and left a slight earthy re» 
Biduum. Six hundred grains of the bark 
loaded with it were lixiTitfted with water, and 
afforded 320 grains of a light salt, resembling 
in colour a light wood, and composed of 
short needles uhited in radiL It was not 
deliquescent; and though the crystals did 
not form till the solution was greatly caa- 
densed by eraporation, it is not rery soluble^ 
since 1000 parts of water dissolve but 35 
with heat, anid 15 in the cold. 

lliis salt was found to be a compound of 
lime and a peculiar vegetable actd, with some 
extractive matter. 

To obtain the acid separate, M. Klaproth 
decomposed the calcareous salt by acetate of 
lead, and separated the lead by sulphuric 
add. He likewise decomposed it directly by 
sulphuric add. Hie product was stall more 
like sucdnic add in taste ; was not deliques- 
cent ; easily dissolved both in water and al- 
cohol ; and did not predpitate the metallic 
solutions, as it did in combination with lime* 
Twenty grains bdng sli^tly heated in a- 
small glass retort, a number of drops of an 
add liquor first came over ; next a concrete 
salt arose^ that adhered flat against the top 
and part of the neck of the retort, in the form 
of prismatic crystals, colourless and trans- 
parent ; and a coaly residuum remained. Hie 
add was then washed out, and crystallised by 
spontaneous evaporation.— Hius sublimation 
appears to be the best mode of purifying the 
salt, but it adhered too strongly to the lime 
to be separated from it directly by heat with- 
out bdng decomposed. 

Not having a suffident quantity to deter- 
mine its specific characters, though he con- 
ceives it to be a peculiar add, coming nearest 
to the sucdnic both in tasle and other quali- 
ties, M. Klaproth has provisionally given it 
the name of moroxylic, and the oslcareous 
salt containing it that of moroxylate of lime. 

ACID (MUCIC). This add has been 
generally known by the name of iacchotaciiCf 
because it was first obtained from sugar of 
milk ; but all the gums appear to afford it. 
Though it is still principally made from su- 
gar of milk, chemists in general distanguish 
it by the name of mudc add. 

It was discovered by Scheele. Having 
poured twelve ounces of diluted nitric add on 
four ounces of powdered sugar of milk in a 
glass retort on a sand bath, the mixture be- 
came gradually hot, and at length effervesced 
violently, and continued to do so for a con- 
siderable time after the retort was taken from 
the fire. It is necessary therefore to use a 
large retort, and not to lute the recdver too 
tight The effervescence having neariy sub- 
sided, the retort was again placed on the sand 
heat, and the nitric acid distilled off, till the 
had acquired a yellowish colour. Hits 



exhibitinf no crystals, dgbt ounoes mora of 
the same add were added, and the distillation 
repeated, till the yellow colour of the fluid 
disappeared. As the fluid was inspissated 
by cooling, it was redissolved in eight ounces 
of water, and filtered. The filtered liquor 
held oxalic add in solution, and seven drams 
and a half of white powder remained on the 
filter. This powder was the add under con^ 
sideration. 

If one part of gum be heated gently with 
two of nitric add, till a small quantity of ni* 
trous gas and of carbonic add is disengaged, 
the dissolved mass will deposit, cm eooling, 
the mucic add. According to Foureioy and 
Vauquelin, different gums yidd from l4 to 
26 hundredths of this add. 

Hiis pulverulent add is soluble in about 
60 parts of hot water, and by cooling, a fourth 
part separates in small shining scales, tbaC 
grow wliite in the air. It decomposes the 
muriate of baryta, and both the nitrate and 
muriate of limcu It acts very little on the 
metals, but forms with thdr oxides salts 
scarcely soluble. It predpitates the nitratea 
of silver, lead, and mercury. With potash it 
forms a salt soluble in dgbt parts of boiling 
water, and crystallizable by cooling. Hiat of 
soda requires but five parts of water, and i» 
equally crystallizable. Both these salts ai« 
still more soluble when the add is in excess. 
That of ammonia is deprived of its base bj 
heat Hie salts of baryta, lime, and mag- 
nesia, are neariy ins<^uble. 

Mudc or saccholactic add has been ana- 
lysed recently with much care: 

Hydrogen. Carbon. Oxygen. 
ByLussac, 3.62 4^a69 4-62.69 aslOO 

BerzeUus, 5. 105-i-33.430-j-6].465=r]00 
From saclactate of lead, Beraelius has in- 
ferred the prime equivalent of the add to be 

lai. 

ACID (MURIATIC). Hie Hydbo. 
CHLORIC of the French chemists. Let six 
parts of pure and well dried sea salt be put 
into a glass retort, to the beak of which is 
luted, in a borisontal direction, a long glass 
tube artificially refrigerated, and containing 
a quantity of ignited muriate of lime. Upon 
the salt pour at intervals five parts of concen- 
trated oil of vitriol, through a syphon funnel 
fixed air-tight in the tubulure of the retorL 
Hie free end of the long tube bdng recurv- 
ed, so as to dip into the mercury of a pneu- 
matic trough, a gaa will issue, which, on 
coming in contact with the air, will form a 
visible doud, or haze, presenting, when 
viewed in a ririd light, prismatic colours. 
This gas is muriatic add. 

When recdved in glass jan over dry mer- 
cury, it is invisible, and possesses all the me- 
chanical properties of air. Its odour is pun- 
gent and peculiar. Its taste add and com- 
sive. Its spedfic grarity, according to Sir 
H. Davy, is such, that 100 cubic inches weigh 



ACID 



65 



MURIATIC. 



99 ptim, wbSie by catuDation, he ujs, they 
oii^ to be d&4 gr. By the ktler number 
the speciiic gntvity, comp a red to air, becomes 
1.S590L By the former number the density 
eooes out 1.2800. M. Gay Luasac states 
the sp. gr. at 1.2780. Sir H.'s second num- 
ber makes the prime equivalent of chlorine 
4.43; which comes near to Berselius's latest 
rasttU; while his fint number makes it 4.48. 
(See Cbix>une). As the attraction of mu- 
riatic acid gaa for hygrometric water is Tery 
strong, it is very probable that 38.4 grs. may 
be the more exact weight of 100 cubic inches, 
ngarding the same bulk of air as ^ 30.5. 
(See the Tid>ie of Gases). If an inflamed 
taper be ioamcned in it, it is instantly extin- 
guished. It is destructiye of aninuil lile ; 
but the irritation produced by it on the epi- 
gfettitt scarcely permits its descent into the 
longs. It is merely changed in bulk by al- 
terations of temperature; it experiences no 
change of state. 

By sealing up muriate of ammonia and 
snlphnric add in a strong glass tube recurv- 
ed» and causiog them to act on eadi other, 
8tr H. Davy procured liquid muriatic add.* 
He justly obsenres, that the generation of 
chtttic substances in close vessels, dtber 
vrith or without heat, offers much more 
powerful means of approximating their mole> 
cules than those dependent on the application 
of cold* whether natural or arti6dal ; for as 

gases diminish only ^^ in volume for eveiy 
degree of Fahrenheit s scale, beginning at 
ordinary temperature, a very sli^^t conden- 
sation only can be produced by the most 
powerful freezing mixtures, not half as much 
aa would result from the application of a 
strong flame to one part of a glass tube» the 
other part being of ordinary temperature: 
and when attempts are made to condense 
gases into liquids by sudden mechanical 
compression, the beat instantly generated 
presents a formidable obstade to the success 
of the experiment ; whereas in the compres- 
sion resulting from their slow generation in 
close Tesselsy if the process be conducted 
with oonomon precautions, there is no source 
of difficulty or danger ; and it may be easily 
asasted by artificial cold, in cases where gases 
approach near to that pdn^ of compression 
and temperature at which they become vfr> 
pours. — PkiL Trans. 1823. 

When potassium, tin, or sine, is heated in 
contact with this gas over mercury, one-half 
of the volume disappears, and the remainder 
is pure bydrc^n. On examining the solid 
residue, it is found to be a metallic chloride. 
Hence muriatic add gas consists of chlorine 
and hydrogen, united in equal volumes. This 
view of its nature was originally given by 
Schede, thongh^obscured by terms derived 
from the vague and risionary hypothesis of 
phlogiston. The FVendi school afterwards 
introduced the belief that muriatic acid gas 



was a compound of an unknown radical and' 
water; and that chlorine consisted of thb 
radical and oxygen. Sir H. Davy has the 
distinguished glory of refuting that hypo- 
thesis, and of proving, by decisive experi- 
ments, that in the present state of our know- 
ledge, chlorine must be regarded as a simple 
substance, and muriatic add gas as a com- 
pound of it with hydrogen. 

The gaseous add unites rapidly, and in 
Unge quantity, vrith water. The following 
table of its aqueous combinations was con- 
structed after experiments made by Mr £. 
Davy, in the laboratory of the' Royal Insti- 
tution, under the inspection of Sir H. Davy. 

At temperature 45^, barometer 30. 
100 parts of solution 

of muriatic gas in Of muriatic add 

water, of specific gra- * gas, parts, 

vity 

1.21 contain 42.43 

1.20 40.80 

1.19 38.38 

1.17 34.34 

1.16 32.38 

1.15 30.30 

1.14 2a28 

1.13 26.26 

1.12 2424 

1.11 22.30 

1.10 20.20 

1.09 iai8 

1.08 1& 16 

1.07 14.14 

1.06 12.12 

1.05 10.10 

1.04 ao8 

1.03 &06 . 

1.02 4.04 

1.01 2.02 

At the temperature of 40^ Fahrenhdt, 
water absorbs about 480 times its bulk of 
gas, and forms solution of muriatic add gas 
in water, the spedfic gravity of which is 
1.2109.— 5!tr H, Davy's EUmerUs. 

In the Annals of FhUoaopby for October 
and November 1817, there are two papera 
on the constitution of liquid muriatic add, 
with tables, by myself, which cdndde nearly 
with the preceding results. They were 
founded on a great number of experiments 
carefully performed, which are detailed in 
the October number. In mixing strong 
liquid add vrith water, I found ttuit some 
heat is evolved, and a small condensation of 
volume is experienced, contrary to the ob- 
servation of Mr Kirwan. Hence this add 
forms no longer an exception, as that emi- 
nent chemist taught, to the general law of 
condensation of volume which liquid adds 
obey in thdr progressive dilutions. Hither- 
to, indeed, many chemists have, without due 
consideration, assumed the half sum or arilA- 
metical mean of two spedfic gravities, to be 

£ 



ACID 



66 



MURIATIC. 



the truly ctmpuUd odmo; and oo coni|Miw 
nig the number thus obtained with that 
derived from experiment, they have inferred 
the change of volume occasioned by chemical 
cmnbination. The errors into which this £ah& 
mode of computation leads are excesriveiy 
great, when the two bodies difier considei»- 
bly in their specific gravities. A view of 
these erroneous results was given in my third 
table of sulphuric acid, published in the 7th 
number of the Journal of Sciences and the 
Arts, and reprinted in this Dictionary, arti* 
de SFBcmc G&Avmr. When, however, the 
two specific gravities do not difier much, the 
errors become less remarkable* It is a 
ringuhir fact, that the arithmetical mean, 
whidi is always greater than the righUy com- 
fmted mean specific gravity, gives, in the case 
of liquid muriatic add, an error in excess, 
very nearly equal to the actual increase of 
densi^. The curious coinddence thus acd- 
dentally produced between accurate experi- 



ments and a fidae mode of ralnilationi is 
very instructive, and ought to lead chemisto 
to verify every anomalous phenomeooa by 
independent modes of reseaiieh. Had Bfr 
Kirwan, for example, put into a mody gra- 
duated tube 50 measures of strong muriatic 
add, and poured gently over it 50 measurea 
of water, he would have found, after agita- 
tion, and coding the mixture to its former 
temperature, that there was a deddcd dimi- 
nution of volume^ as I experimentally asccr- 
tdned. 

Having had ocoaskm more latdy to sub- 
ject muriatic add, in difieient states of dilu- 
tion, to a very rigorous examination, I per- 
cdved small deviations in the new resulta 
from my former tabular quantitiei, which in- 
duced me to revise the whole with the great- 
est possible care, both in experiment and 
calculation. The following Table I bdiev» 
to Kpproiuch very near iA the truth. 



TABLE of MURIATIC ACID, by Da Ubs. 



Add. 




t 


Add 








lACM 








ofl JO 


S|ieclflc 


Ohio. 


Muriatic 


oXlJiO 


flpedflc 


ChkK 


Muristic 


ofl.«0 


Specific 


C3ilo. 


Muriatie 


InlOa 


grsTity. 


rine. 


Gaa. 


inioa 


gravity. 


fine. 


Gaa. 


in 10(1. 
32 


gravity. 


rinc 


Oaa. 


100 


1.2000 


39.675 


40.777 


66 


1.1328 


26.186 


26.913 


1.0687 


12.697 


iao49 


99 


1.1982 


39.278 


40.369 


65 


1.1308 


25.789 


26.505 


31 


1.0617 


12.300 


12.641 


98 


1.1964 


38.882 


39.961 


64 


1.1287 


25.392 


26.098 


30 


1.0597 


11.903 


12.233 


97 


1.1946 


38.485 


39.554 


63 


1.1267 


24.996 


25.690 


29 


1.0577 


11.506 


11.825 


96 


1.1928 


38.089 


39.146 


62 


1.1247 


24.599 


25.282 


28 


1.0557 


11.109 


11.418 


95 


1.1910 


37.692 


3a738 


61 


1.1226 


24.202 


24.874 


27 


1.0537 


10.712 


11.010 


94 


1.1893 


37.296 


3&330 


60 


1.1206 


23.805 


24.466 


26 


1.0517 


10.316 


10.602 


93 


1.1875 


36.900 


37.923 


59 


1.1185 


2^408 


24.058 


25 


1.0497 


9.919 


10.194 


92 


1.1857 


36.503 


37.516 


58 


1.1164 


23.012 


2a650 


24 


1.0477 


9.522 


9.786 


91 


1.1846 


36.107 


37.108 


57 


1.1143 


22.615 


2&242 


23 


1.0457 


9.126 


9.379 


90 


1.1822 


35.707 


36.700 


56 


1.1123 


22.218 


22.834 


22 


1.0437 


a729 


a971 


89 


1.1802 


35.310 


36.292 


55 


1.1102 


21.822 


22.426 


21 


1.0417 


a332 


a563 


88 


1.1782 


34.913 


35.884 


54 


1.1082 


21.425 


22.019 


20 


1.0397 


7.935 


a 155 


87 


1.1762 


34.517 


35.476 


53 


1.1061 


21.028 


21.611 


19 


1.0.377 


7.538 


7.747 


86 


1.1741 


34.121 


35.068 


52 


1.1041 


20.632 


21.203 


18 


1.0357 


7.141 


7.340 


85 


1.1721 


3a 724 


34.660 


51 


1.1020 


20.235 


2a796 


17 


1.0337 


6.745 


6.932 


84 


1.1701 


33.328 


34^252 


50 


1.1000 


19.837 


^.388 


16 


1.0318 


6.348 


6.524 


88 


1.1681 


32.931 


33.845 


49 


1.0980 


19.440 


19.980 


15 


1.0298 


5.951 


6.116 


82 


1.1661 


32.535 


3a437 


48 


1.0960 


19.044 


19.572 


14 


1.0279 


5.554 


5.709 


81 


1.1641 


32.136 


33.029 


47 


1.0939 


18.647 


19.165 


13 


1.0259 


5.158 


5.301 


80 


1.1620 


31.746 


32.621 


46 


1.0919 


ia250 


ia757 


12 


1.0239 


4.762 


4.893 


79 


1.1599 


31.343 


32.213 


45 


1.0899 


17.854 


18.349 


11 


1.0220 


4.365 


4.486 


78 


1.1578 


30.946 


31.805 


44 


1.0879 


17.457 


17.941 


10 


1.0200 


a968 


4.078 


77 


1.1557 


30.550 


31.398 


43 


(.0859 


17.060 


17.534 


9 


1.0180 


a571 


a670 


76 


1.1536 


3a 153 


30.990 


42 


1.0838 


16.664 


17.126 


8 


1.0160 


ai74 


a262 


75 


1.1515 


S^.757 


30.582 


41 


1.0818 


16.267 


16.718 


7 


1.0140 


2.778 


2.854 


74 


1.14^ 


29.361 


30.174 


40 


J. 0798 


15.870 


16.310 


•6 


1.0120 


2.381 


2.447 


73 


1.1473 


28.964 


29.767 


39 


1.0778 


15.474 


15.902 


5 


1.0100 


1.984 


2.039 


72 


1.1452 


2a567 


29.359 


38 


1.0758 


15.07r 


15.494 


4 


1.0080 


1.588 


1.631 


71 


1.1431 


28.171 


28.951 


37 


1.0738 


14.680 


15.087 


3 


1.0060 


1.191 


1.224 


70 


1.1410 


27.772 


2a544 


36 


1.0718 


14.284 


14.679 


2 


1.0010 


0.795 


0.816 


69 


1.1389 


27.376 


2ai36 


35 


1.0697 


ia887 


14.271 


1 


1.0020 


a397 


0.408 


68 


1.1369 


26.979 


27.728 


31 


1.0677 


ia490 


ia863 










67 


1.1349 


26.583 


27.321 


< 33 


1.0657 


ia094 


ia456 











ACID 



67 



MURIATIC. 



At the denritj 1.199, Mr Dahon's table* 
bes 25.6 per cent of real muriatic add by 
weighty eqitivaleiit to only 32. 9 cblorine, io- 
stcad of 39.47, which I betiere to be the ei- 
acC Tahie. If we term the correct quantity 
100^ then Mr Dalton's number would be 
only 83 ; which is no less than 17 per cent 
of defect from the truth. I Mve purposely 
omitted in this new table the column of dry, 
or, as it was also called, real muriatic add ; 
first, because there is no eridence at pre s e nt 
of the existence of any such body ; and se- 
condly, because, though it was a convenient 
column for finding by inspection the increase 
of weight which any saliBable base would ac- 
quire by aaturatioa with the liquid acid, yet 
that convenience may be obtained by the fol- 
lowing simple calculation. Since the prime 
equrtalent of chlorine is to that of the sup- 
posed dry muriatic add in the ratio of 45 to 
35^ or 9 to 7 ; if we multiply the number 
opposite to the given spedfic gravity, in the 
chlorine column, by 9, and divide by 7, we 
shall have the rriative quantity of ihejixable 
mnriatic add.«-Vovm. of Science, zii. 267. 
' From the curious coinddence above no^ 
tieed, vre derive a very simple rule for find- 
ing tile approziBMte value of chlorine in the 
liquid add at any density. Multiply the 
derimal part of the number representing the 
spedfic gravity by 200, the product will be 
the chlorine present in 100 parts. Thus, 
the specific gravity is 1.0437, what is the 
quantity per cent of chlorine? 0.0437 X 
800^ &74. Now the tabular number is 
&729. The sp. gravity bdng 1.059, what 
18 the value of the chlorine in 100 parts? 
aO59x200=rll.a The table has 1 1.9. 
Towards the head of the table this rule gives 
a slight error in excess, and towards the 
toot an equally slight error in defect ; but the 
approximation is always good enough lor 
oidinaiy practice, sekkun amounting to one. 
half per cent. If to the number thus finind 

for chlorine we add -^ part, the sum is the 
corresponding weight of muriatic add gas. 

We have seen it stated, that water, in ab- 
sorbing 480 times its bulk of the add gas, 
becomes of spedfic grarity 1.2109. If we 
compute from these tlata the increase of its 
bHik, we shall find it equal to 1.42, or nearly 
one and a half the volume of the water. 
461 parts occupy only 1.42 in bulk, a con- 
densation of about 340 into one. Ihe con- 
sequence of this approximation of the parti- 
da is the evolution of tbdr latent beat ; aAd 
accordingly the heat produced in the conden- 
sation of the gas is so great, that it mdts ice 
almost as rapidly as the steam of boiling 
water does. Hence also, in passing the gas 
fnmi tile beak of a retort into a Woolf)e*s ap- 
paratus containing water to be impregnated, 
itis necessary to surround the botties with 

• New System of Chenucal PbUoiophy, U. p^ S9Sk 



cold water or ice, if we wish a contidersble 
condensation. 

By uniting the base of this gas with sOver, 
and also with potassium, Bersdius determin- 
ed the prime equivalent of muriatic add to 
be 3.4261, whence chlorine comes out 4.4261, 
and muriatic gas 4i4261 -f- 0. 125 (the prime 
of hydrogen) =: 45511. But if we take 
1.2847 as the spedfic grarity of this add gas, 
then the speciBc gnrity of chlorine will be 
twice that nomber, minus the spedfic gravity 
of hydrogen, or (1.2847 X S) — 0.0694 ss 
2.5; and as dilorine and hydrogen unite 
volume to volume^ then the relatioki of the 
prime of chlorine will be to that of hydrogen 

=r-^=r36. If we diride tiiis by 8, 
0.0694 ' 

we shall have 4.5 to represent the prime 

equivalent of chlorine, and 4.5-^-0.125=; 

4.625, for that of muriatic add gas. 

Muriatic add, firom its composition, has 
been termed by M. Gay Lussac the hjfdro- 
chloric add ; a name (rf>jected to on good 
grounds by Sir H. Davy. It was prepared 
by the older chemists in a very rude manner, 
and was called by them Spirit of Salt 

Muriatic was andoitly extracted from com- 
mon salt, by igniting a mixture of it and soft 
clay kneaded up together. 

Sir H. Davy first gave the just exphina- 
tion of this decomposition. Common salt is 
a compound of sodium and chlorine. T!ie 
sodium may be concdved to combine with 
the oxygen of the water in tiie earth, and with 
the earth itself, to fiirm a ritreoos compound ; 
and the chlorine to unite with the hydrogen 
of the water, forming muriatic add gas. *' It 
is also easy,** adds he, " according to these 
new ideas, to explain the decomposition of 
salt by moistened litfaarge, the theory of 
which has so much perplexed the most aoute 
chemists. It may be concdved to be an in- 
stance of compound affinity : the chlorine is 
attracted by the lead, and the sodium com- 
bines with the oxygen of the Utbarge^ and 
with water, to form hydrate of soda, which 
gradually attracts carbonic add from the air. 
When common salt is decomposed by otl of 
vitriol, it was usual to explain the phenome- 
non by saying, that the acid, by its superior 
affinity, aided by heat, expelled the gas, and - 
united to the soda. But as ndther muriatic 
add nor soda exists in common salt, we must 
now modify the explanation by sayin^^ that the 
water of the oil of vitriol is first decomposed, 
its oxygen unites to the sodium to form soda, - 
which is sdzed on by the sulphuric add, 
while the chlorine combines with the hydro- 
gen of the water, and exhales in the form of 
muriatic add gas.** 

As 100 parts of dry sea salt are capable of • 
yielding 62 parts by wdgbt of muriatic acid 
gas, these ought to afl^rd, by economical - 
management, nearly 221 -parts of liquid acid, 
spedfic grarity 1.142, as prescribed by the 



ACID 



68 



MURIATIC. 



London CoUcge, or SOO parts of acid, qi. gr. 
1.160, as directed bj the Edinbuigh aod 
Dublin Fhannaoopfsias. 

llie fluid ounce of the London College be- 
ing 1-1 6th of a wine pint, is equal in weight 
to 1.265817 lbs. Troy, divided by 16, which 
gives 453.7 grains Troy. This weight mul- 
tiplied by 1. 142, ^ the specific gravity of 
their standard acid, gives the product 520.4 ; 
which being multiplied by 0.2874^ the mu- 
riatic gas in 1.00 by my table^ we have 
149.56 for the acid gas in the liquid ounce 
of the above density. We find this quantity 
equivalent to 203 gr. of carbonate of lime. 
When this add is contaminated with sulphu- 
ric acid, it affords precipitates with muriates 
of baryta and strontia. 

The English manufacturers use iron stills 
for this distillation, with earthen heads. 

Hie muriates, when in a state of dryness, 
are actually dilorides, consisting of dilorine 
and the metal ; yet they may be conveniently 
treated of under the title muriates 

Muriate of baryta crystallises in tables 
bevelled at the edges, or in octaedral pyra- 
mids applied base- to base. It is soluble in 
five parts of water at 60^, in still less at 
a boiling heat, and also in alcohol. It is not 
altered in the air, and but partly decompos- 
able by heat. The sulphuric acid separates 
its base; and the alkaline carbonates and 
sulphates decompose it by double affinity. It 
is best prepared by dissolving the carbonate 
in dilute muriatic acid ; and if contaminated 
with iron or lead, which occasionally happens, 
these may be separated by the addition of a 
small quantity of liquid ammonia, or by 
boiling and stirring the solution with a little 
baryta. M. Goettling recommends to pre- 
pare it from the sulphate of baryta; eight 
parts of which in fine powder are to be mixed 
with two of muriate of soda, and one of 
charcoal powder. This is to be pressed hard 
into a Hessian crucible, and exposed for an 
hour and a half to a red beat in a wind fur- 
nace. The cold mass, being powdered, is to 
be boiled a minute or two in sixteen parts of 
vrater, and tlien filtered. To this liquor 
muriatic acid is to be added by little and 
little^ till sulphuretted hydrogen ceases to be 
evolved ; it b then to be filtered, a little hot 
water to be poured on the residuum, the liquor 
evaporated to a pellicle, filtered again, and 
then set to crystallize. As the muriate of 
soda is much more soluble than the muriate 
of baryta, and does not separate by cooling, 
the muriate of baryta will crystallize into a 
perfectly white salt, and leave the muriate of 
soda in* the mother water, which may be 
evaporated repeatedly till no more mini- 
ate of baryta is obtained, lliis salt was 
first employed in medicine by Dr Crawford, 
chiefly in scrofulous complaints and cancer, 
beginning with doses of a few drops of the 
saturated solution twice a^ay, and increas- 



ing it gradually, as far as forty or fifty drops 
in some instances. In large doses it excites 
nausea, and has ddeterious effects. As a 
test of sulphuric add, it is of great use. 

Mr Fhfllips states the composition of the 
crystals to be 1 atom chloride of barium ^ 2 
atoms water. 

Muriate of potash, fiarmeriy known by the 
names of/elfr^uge fall ofSylvna, crystallizea 
in regular cubes, or in rectangular parallelo- 
pipedons; decrepitating on the fire. Their 
taste is saline and bitter. Hiey are soluble 
in thrice their weight of cold water, and io 
but little less of boiling water, so as to r»> 
quire spontaneous evaporation for crystallis- 
ing. Fourcroy recommends to cover the 
vessel vrith gause, and suspend bain in it, 
for the purpose of obtaining regular crystals. 

It is sometimes prepared in decomposing 
sea salt by common potash for the purpose 
of obtaining soda ; and may be formed by 
the direct combinatioQ of its constituent 
parts. 

Muriate of soda, or coaunois taU^ is of 
ccmsiderable use in the arts, as well as a 
n ecess ary ingredient in our food. It crys- 
tallises in cubes, which are sometimes grou|K 
cd together in various ways, and not unfre- 
quently form hollow quadrangular pyramida. 
In the fire it decrepitates, melts, and is at 
length volatilised. When pure it is not de> 
liquescent One part is soluble in 2} of 
cold water, and in little less of hot, so that 
it cannot be crystallised but by evaporation. 

Common salt is found in large masses, or 
in rocks under the earth, in England and 
elsewhere. In the solid form it is called soi 
gem, or rode iali. This rock salt is never 
used on our tables in its crude state, as the 
Polish rock salt is. 

The waters of the ocean eveiTwhere abound 
vrith common salt, though in different pro- 
^portions. Tbe water of the Baltic sea is 
said to contain one sixty-fourth of its weight 
of salt ; that of the sea between England and 
Flanders contains one thirty-second part; 
and that on the coast of Spain one sixteenth 
part. 

Hie whole art of extracting salt from 
waters which contain it, consists in evaporat- 
ing the water in the cheapest and most con- 
venient manner. 

There is no difference between this salt 
and the lake salt extrscted from different 
lakes, excepting such as may be occasioned 
by the casual intervention of some substances. 

At several places in Germany, and at Mont- 
marot in Francei, the waters of salt springs 
are pumped up to a large reservoir at the 
top of a building or shed; from which it 
drops or trickles through small apertures 
upon boards covered vrith brushwood. Hie 
large surface of tbe water thus exposed to 
the air causes a very considerable evapora- 
tion ; and the brine is aAerward conveyed to 



ACID 



69 



MURFATIC. 



tiie boflmi for the perfect mpuMaoa of the 
ealt 

To fi«e oommon salt from those mixtures 
that render it deliquescent, and less fit for 
the purposes to which it is applied, it n»y be 
put into a conical Tesael with a small aper* 
ture at the point, and a saturated solution of 
the muriate of soda bailing hot be poured on 
iL This solution will dissoWe and carry off 
any other salts mixed with the soda, and 
leaive it quite purs^ by repeating the process 
three or (bur times. 

At present, the greater part of the carbo- 
nate of soda in the market is furnished by 
deoompoeing the sulphate of soda left, after 
the chlorine is expelled in the usual way of 
efiminating it from oommon salt Mix the 
sulphate of soda with an equal weight of 
ehallc, and rather more than half its weight 
of charcoal powder, and expose the mixture 
in a revnberatory furnace to a heat sufficient 
to bring them to a state of imperfect lique- 
fiKtion. Much of the sulphur Ibrmed will 
be expelled in Tapour and burned, the mix- 
ture being frequently stirred to promote this ; 
and thia is continued till the mass on cooling 
assumes a fine grain. It is then left exposed 
to a humid atmosphere, and the carbonate of 
soda may be extracted by lixiviation, the sul- 
phur not consumed haying united with the 
lime. 

Beside its use in seasoning our food, and 
piese rt i ng meat both for domestic consump- 
tion and during the longest voyages^ and in 
frimiahing us with the muriatic add and 
soda, sah fivrms a glaxe for coarse pottery, 
by being thrown into the o?en where it is 
baked; it improres the whiteness and clear- 
ness of glass; it gives hardness to soap ; in 
melting metals it preserves their surfiice from 
calcination, by defending them from the air, 
and is employed with advantage in some 
assays ; it is used as a mordant, and for im- 
proving certain colours, and enters' more or 
less into many other processes of the arts. 

Muriate of strontia crystallises in very 
slender hexagonal prisma, has a cool pungent 
taster without the austerity of the muriate of 
baryta, or the bitterness of the muriate of 
Inne; is soluble in 0.75 of water at 60^, 
and to almost any amount in boiling water; 
is likewise soluble in alcohol, and gives a 
blood-red colour to its flame. 

It haa never been found in nature, but 
may be prepared in the same way as the 
muriate <^baiyta. 

Muriate of lime crystallises in hexaedral 
prisms terminated by acute pyramids; but 
if the solution be greatly concentrated, and 
exposed to a low temperature, it is condensed 
in confused bundles of ncedly crystals. Its 
taste is acrid, bitter, and very disagreeable. 
It is soluble in half its weight of cold water, 
and by heat in its own water of crystalliza- 
It is one of the most deliquescent 



salts known ; and when deliquesced has been 
called cU of Ume, It exists in nature^ but 
neither very abundantly nor very pure. Jt 
is formed in chemical laboratories, in the 
decomposition of muriate of ammonia ; and 
Homberg found, that if it were urged by a 
violent beat till it condoosed, on cooling, into 
a ritreous mass, it emitted a phosphoric light 
upon being struck by any hard body; in 
which state it was called Homberg*i Fko^ 
phonu. 

Muriate of ammonia has long been known 
by the name of tal ammorua or ammoniae* 
It is found native in the neighbourfaood of 
volcanoes, where it is sublimed sometimes 
nearly pure) and in different parts of Asia 
and Africa. A great deal is carried annual- 
ly to Russia and Siberia from Bucbarian 
Tartary; and we formerly imported large 
quantities from £^gypt, but now manu&cture 
it at home. See Ammonia. 

Tins salt is usually in the form of cakes^ 
with a convex surface on one side, and con- 
cave on the other, from being sublimed into 
large globular vessels ; but by solution it may 
be obteined in regular quadrangular crystals. 
It is remarkable for possessing a certain de^ 
gree of ductility, so that it is not easily pul- 
verable. It is soluble in 3^ parts of water 
at GOP, and in little more than its own wei^t 
of boiling water. Its taste is cool, acrid, and 
bitterish. Its spediic grarity is IA2. It at- 
tracts moisture from the air but very slightly. 

In tinning and soldering, it is employed 
to preserve the surface of the metals fVom 
oxidation. In assaying, it discovers iron, 
and separates it from some of its combina- 
tions. 

Muriate of magnesia is extremely deliques- 
cent, soluble in an equal weight of water, 
and difficultly crystallizable. It dissolves 
also in five parts of alcohol. It is decom- 
posable l>y heat, which expeb its add. Ite, 
taste is mtensely bitter. 

With ammonia this muriate forms a triple 
salt, crystaUizable in little polyedrons, which 
separate quickly from the water, but are not 
very regularly formed. Its taste partakes of 
that of both the preceding salts. The best 
mode of preparing it is by mixing a solution 
of 27 parts of muriate of ammonia with a 
solution of 73 of muriate of magnesia ; but 
it may be formed by a semi-decomporition of 
either of these muriates by the base of the 
other. It is decomposable by heat, and re^ 
quires six or seven times its weight of water 
to dissolve it. 

Muriate of gludna appears to crystaUixe 
in very small crystals ; to be decomposable 
by heat ; and, dissolved in alcdiol and diluted 
with water, to form a pleasant saccharine 
liquor. 

Muriate of alumina is scarcely crystelliz- 
able, as on evaporation it assumes the state of 
a thick jelly. It has an add, styptic, acrid 



ACID 



70 



CHXOaiC. 



tMlfe It M OLlraBely tolubto in water, md 
ddiqtMtoent. Fire deoompoMS h. It m^ 
b^ prapared by directly oombining the muri- 
atic add with alamina, but the acid always 
icmaiBs ia excess. 

Muriate of lireonia crystallises io small 
needles, which are very soluble^ attract mois- 
taref and lose their transparency in tbe air. 
It has an austere taste, with somewhat of 
acrimony. It is decomposable by heat Tbe 
gallic acid precipitates from its solution, if it 
be five from iron, a white powder. Carbo- 
nate of ammonia, if added in excess, redis- 
solves the predpitato it had before thrown 



Muriate of yttria does not crystallize when 
esaporsted, but forms a jelly : it dries with 
difficulty, and deliquesces. See Salt. 

ACID (MURIATIC, OXYGENAT- 
ED). See Chlorins. 

ACID (MURIATIC, OXYGENIZ- 
ED). This supposed acid was lately describ- 
ed fa^ M. Hienard. He saturated common 
muriatic add of moderate strength with deut- 
oxide of barium, reduced into a soft paste by 
trituration with water. He then predpi- 
tated the baryta finom the liquid, by adding 
the requisite quantity of sulphuric add. He 
next took this oxygenixed muriatic add, and 
treated it with deiffcoxide of barium and sul- 
phuric add, to oxygenate it anew. In this 
way he charged it with oxygen as often as 15 
times. He thus obtsined a liquid add, which 
oontained 32 times its Tolume of oxygen at 
the temperature of 68° Fahr. and at tbe or- 
dinary ataoospherical pressure, and only 4^ 
times its rolume of muriatic add, which gives 
about 88 equivalent primes of oxygen to 1 
of muriatic add. For the ratio of oxygen 
to the add, by weight, is 1 to 4.6 ; but by 
measure the ratio will be as these two num- 
bers respectively divided by the spedfic gra- 
vity of the gases, or as j^^ tp j^ 

which by reduction makes nearly one volume 
of oxygen, equivalent to four of muriatic add. 
Now, the oxygen in the above result, instead 
of bdng l-4th of the volume of the add gas, 
was seven times greater, whence we derive 
the number 28. Still more oxygen may 
however be added. On putting the above 
oxygenized add in contact with sulphate of 
silver, an insoluble chloride of this metal sub- 
sides, and the liquid is oxygenized sulphuric 
add. When this is passed through the 61ter, 
muriatic add is added to it, but in smaller 
quantity than existed in the original oxygen- 
ized add. A quantity of baryta, just suffi- 
dent to predpitate the sulphuric add, is then 
added. Instantly the oxygen, leaving the 
sulphuric add to unite with the muriatic acid, 
brings that add to the highest point of oxy- 
genation. Thus we see that we can transfer 
the whole of the oxygen from one of these 
acids to the other : and on a little reflection 
it will be evident, that to obtain sulphuric 



add m the highest degree of oxygenalioii, it 
will be merely necessary to pour baryta 
water into oxygenated sulphuric acid, so as 
to predpitate only a part of the add. 

All these operations, with a little practice^ 
may be performed without the least diflkulty. 
By combining the two methods just describ- 
ed, M. Themird found that he could obtain 
oxygenized muriatic add, containing nearly 
16 times as many volumes of oxygen as of 
muriatic add; which represents about 64 
equivalent primes of the former to 1 of the 
latter. This oxygenised add leaves no resi- 
duum when evaporated. It is a very add 
eolourle» liquid, almost destitute of smcU, 
and powerfully reddens turnsole. When 
boiled for some time^ its oxygen is expdled. 
It dissolves zinc without effervescenee. Ito 
action on the oxide of silver is curious. Ihcae 
two bodies occasion as lively an effervescence 
as if an add were poured upon a carbonate^ 
Water and a chloride are formed, while the 
oxygen is evolved. This oxide enables us to 
detmiine the quantity of oxygen present in 
the oxygenised add. Pour mercury into a 
gradusitod glass tube, leaving a small deter- 
minate space, which must be filled with the 
above add, invert the tube in mercury, let 
up oxide ofsilver diffused in water; instantly 
the oxygen is separated. 

We ought, however, to regard this appi^ 
rent oxygenation of the acid, merdy as the 
conversion of a portion of its combined water 
into deotoxide of hydrogen. Hie same ex- 
pUmation may be extended to the other oxy- 
genised adds of M. Tbenard. See Watjuu 

ACID (CHLORIC). We place this acid 
after the muriatic add, because it has chlo- 
rine abo for its base. It was fint eh'minat- 
ed from the salts oontsining it by M. Gi^ 
Lussac, and described by him in bis admira- 
ble memoir on iodine^ published in the 91st 
volume of the Annale$ de Chimie. When a 
current of chlorine is passed for some time 
throo^ a solution of barytic earth in warm 
water, a substance called hyperoxymuriate of 
baryta by ite first discoverer, M. Cheneviz, 
is formed, as well as some common muriate. 
The latter is separated, by boiling phosphate 
of silver in the compound solution. Hie 
former may then be obtained by evaporation, 
in fine itiomboidal prisms. Into a dilute 
solution of this salt, M. Gay Lusaac poured 
weak sulphuric add. Though he added 
only a few drops of add, not nearly enough 
to saturate tiie baryta, the liquid became sen- 
sibly add, and not a bubble of oxygen escaped. 
By continuing to add sulphuric add with 
caution, he succeeded in obtaining an add 
liquid entirdy free from sulphuric add and 
bvyta, and not predpitating nitrate of silver. 
It was chloric add dissolved in water. Ite 
characters are the following :— 

Hiis add has no sensible smelL Ite so- 
lution in water is perfectly colourless. Its 



ACID 71 CHLORIC. 

fBrte it toy acid, and H reddens b'trnns with- netly hy saturating the aOcaH or eartfi with 

OQt destroying the colour. It produces no tbe chloric add, or by the old proc e s s of 

alteration on solution of indigo in sulphuric transmitting chlorine Uirouj^ the solutions 

add. Light does not decompose it. It may of the bases in Woolfe's bottles. In this 

be concentr a te d by a gentle heat, without un- case the water is decomposed. Its oxygen 

dergoing decomposition, or without evaponi- unites to one portion of the chlorine, fonn- 

ting. It was kept a long time exposed to faig chloric add, while its hydrogen unites to 

the air without sensible diminution of its anc»ther portion of dilorine, forming muriatic 

quantity. When concentrated, it has som&> acid ; and hence, chlorates and mnnates must 

tiling of an oily consistency. When exposed be contemporaneously generated, and must be 

to beat, it is partly deconaposed into oxygen afterwnds separated by crystallisation, or po- 

and cblorinei and partly volatilized without culiar methods. 

alteration. Muriatic add decomposes it in The chlorate of potash or hyperoxymuriata 

tiie same way, at Ae common temperature, has been long known. When exposed to a 

finlphurotts add, and sulphuretted hydrogen, red heat, 100 grains of this salt yield 38.8B 

bare the same property ; but nitric add pro- of oxygen, and are converted into the chloride 

doco no diange upon it. Combined with of potassium, oe the dry muriate, Tbis re- 

amnoonia, it forms a fulminating salt, former- mainder of 61.18 gndns consists of 32.19 

1y described by M. Chenevix. It does not potassium and 28.93 chlorine. But 32.19 

pc^edpitate any metallic solution. It readily potassium require 6.50 oxygen, to form the 

disBolves dnc, disengaging hydrogen ; but it potash which existed in the original chlo- 

acts slowly on mercury. It cannot be ob- rate. Hierefore^ subtracting this quantity 

iained in tbe gaseous state. It is compos- ftom 3B.88) we have 32.38 for the oxygen 

ed of I volume chlorine -{-2.5 oxygen, or combined with the chlorine^ constituting 

by wei^ of 100 chlorine -f 111.70 oxy- 61.31 of chloric add, to 3a69 of potash, 

gen, if we consider the spedfic gravity of Chlorate of potash may be procured by 

dilorine to be 2.4866. But if it be called recdving chlorine, as it is formed, into a so- 

2L420, as M. Gay Lussac does in his memoir, lution of potash. When the solution is ss- 

ft wiU then come out 100 chlorine -{- 1 14.7 turated, it may be evaporated gently, and the 

oxygen. Hiis last number is however too first crystals produced will be the salt desired; 

great, in consequence of estimating the spe- this crystallinng before the simple muriate^ 

dfic grstvity cf oxygen 1. 1 11 1, while M. Gay which is produced at the same time with it. 

Lttssae makes it 1.10359. Chloric add is Its crystals are in shining hexaSdral lamin«, 

at any rate a compound of 5 primes of oxy- or rhomboidal plates. 

gen -^ 1 of chlorine ^ 5 -)- 4.5. Its taste is cooling, and ratber unpleasant. 

H. Vauquefin, in making phosphate of Its spedfic gravity is 2.0. Sixteen parts of 
'silver act on the mixed saline solution above water, at 60^, dissolve one of it, and 2f of 
described, tried to accelerate its action by dis- boiling water. The purest oxygen is extract- 
solving it previously in acetic add. But on ed from this salt, by exposing it to a gentle 
evaporating the chlorate of baryta so obtained red heat One hundred grains yidd about 
to dryness, and exposing about 30 gruns to 115 cubic inches of gas. It conaistB' of 9.5 
a decomposing heat, a tremendous explosion chloric add -{- 6 potash ss 15.5, which is 
took place, which broke tbe furnace, rent a the prime equivalent of the salt. It is inca- 
Ifaick plfldna crucible^ and drove its lid into pable of discharging vegetable colours ; but 
the drnnney, where it stuck. It was the em- the addition of a little sulphuric add deve- 
pioyment of acetic add which occasioned lopes this property. So likewise a few gndns 
tfab accident, and therefore it ought never to of it, added to muriatic add, give it this pro- 
be naed in this way. P*^y- 

To the preceding account of tbe properties llie eflffects of this salt on hiflammable 

of cUoric add, M. Vauquelin has added the bodies are very powerful. Rub two grains 

Ibllowf ng :— Its taste is not only add, but into powder in a mortar, add a grain of sulr 

astringent, and its odour, when concentrated, phur, mix them well by gentle trituration, 

is somewlmt pungent. It difTers from chlo- then collect the powder into a heap, and press 

line^ in not predpitating gelatin. When upon it suddenly and forcibly with the pestle, 

paper stained vrith litmua is left for some dme a loud detonation will ensue. If the mixture 

in contact with it, the colour is destroyed, be wrapped in strong paper, and struck with 

Mixed Willi muriatic add, water is formed, a hammer, the report will be still louder, 

and both adds are converted into chk>rine. Five grains of the salt, tnixed in the same 

Sulpborous add is converted into sulphuric, manner with two and a half of charcoal, will 

by taking oxygen from the chloric add, which be inflamed by strong trituration, espedally if 

is consequently converted into chlorine. a grain or two of sulphur be added, but with- 

Cbloric add oombtnes with the bases, and out much noise. If a little sugar be mixed 

forms tbe chlorates, a set of salts formerly vrith half its wdgfat of the chlorate, and a 

known by tbe name of the hyperoxygentied little strong sulphuric add poured on it, a 

muriates. They may be formed dUier di- sudden and vehement inflammation wiULen- 



ACID 



72 



PERCHLORIC. 



sue ; but tfab experiment requires entdoB, es 
well as the following. To one grain of the 
powdered salt in a mortar, add half a grsin of 
phosphorus; it will detonate, with a loud 
report, on the gentlest trituration. In this 
experiment the hand should be defended by 
a glove, and great care should be taken that 
none of the phosphorus get into the eyes. 
Phosphorus may be inflamed by it under 
water, putting into a wine glass one part of 
phosphorus and two of the chlorate^ nearly 
filling the glass with water, and then pouring 
in, through a glass tube reaching to the bot- 
tom, three or four parts of sulphuric add. 
This experiment, too, is very hazardous to the 
eyes. If olive or linseed oil be taken instead 
of phosphorus, it may be inflamed by similar 
means on the surface of the water. This salt 
should not be kept mixed with sulphur, or 
perhaps any inflammable substance, as in 
this state it has been known to detonate 
spontaneously. 

Chlorate of soda may be prepared in the 
same manner as the preceding, by substitut- 
ing soda for potash ; but it is not easy to 
obtain it separate, as it is nearly as soluble 
as the muriate of soda, requiring only three 
parts of cold water. Vauquelin formed it, 
by saturating chloric acid with soda; 500 
parts of the dry carbonate yielding 1100 
parts of crystallized chlorate. It consists of 
4 soda 4" ^'^ *^ = l^^ which is its 
prime equivalent. It crystallizes in square 
plates, produces a sensation of cold in the 
mouth, and a saline taste; is slightly deli- 
quescent, and in its other properties resembles 
the chlorate of potash. 

Baryta appears to be the next base in order 
of affinity for this acid. Hie best method of 
forming it, is to pour hot water on a large 
quantity of this earth, and to pass a current 
of chlorine through the liquid kept warm, so 
that a fresh portion of baiyta may be taken 
up as the former is saturated. Hiis salt is 
soluble in about four parts of cold water, 
and less of warm, and crystallizes like the 
simple muriate. It may be obtained, how- 
ever, by the agency of double affinity ; for 
phosphate of silver boiled in the solution will 
decompose the simple muriate, and the mu^ 
riate of silver and phosphate of baryta being 
insoluble, will both fall down and leave the 
chlorate in solution alone. The phosphate 
of silver employed in this process must be 
perfectly pure, and not the least contaminat- 
ed with copper. 

Hie chlorate of strontia may be obtained 
in the same manner. It is deliquescent, 
melts immediately in the mouth, and pro- 
duces cold ; is more soluble in alcohol than 
the simple muriate, and crystallizes in needles. 

The chlorate of lime, obtained in a similar 
way, is extremely deliquescent, liquefies at a 
low heat, is very soluble in alcohol, produces 



nradiooUia 



and baa a diarp bitter 



Chlorate of ammonia is formed by doable 
affinity, the carbonate of ammonia decompos- 
ing the earthy salts of this genus, giving up 
its carbonic add to their base, and combin- 
ing with their add into chlorate of ammonia* 
which may be obtained by evaporstion. It 
is very soluble both in water and alcohol^ and 
decomposed by a moderate heat. 

The chlorate of magnesia much resemblea 
that of lime. 

To obtain chlorate of alumina, M. Chene- 
vix put some alumina, predpitated from the 
muriate^ and well wadied, but still moisly 
into a Woolfe*s apparatus, and treated it as 
the other earths. The alumina short^ dis- 
appeared ; and on pouring sulphuric add 
into the liquor, a strong smell of chloric 
add was percdvable ; but on attempting to 
obtain the salt pure by means of phosphate 
of silver, the whole was decomposed, and 
nothing but chlorate of silver was found in 
the solution. M. Chenevix adds, however, 
that the aluminous salt appeara to be veiy 
deliquescent, and soluble in alcoboL See 
Salt. 

ACID (PERCHLORIC). If about 3 
parts of sulphuric add. be poured on 1 of 
chlorate of potash in a retort, and, after the 
first violent action is ova*, heat be gradually 
applied to separate the deutoxide of chlorine^ 
a saline mass will remain, consisting of bi- 
sulphate of potash and perchlorate of potash. 
By one or two crystallizatioos, the latter salt 
may be separated from the former. It is a 
neutral salt, with a taste somewhat similar to 
the common muriate of potash. It is very 
sparingly soluble in cold water, since at OOP 
only 3^ is dissolved ; but in boiling water it 
is more solubleu Its crystsls are elongated 
octahedrons. It detonates feebly when tri- 
turated with sulphur in a mortar. At the 
heat of 412^, it is resolved into oxygen and 
muriate of potash, in the proportion of 46 of 
the former to 54 of the latter. Sulphuric 
arid, at 280**, disengages the perchloric add. 
For these facts sdence is indebted to Count 
Von Stadion. It seems to consist of 7 primes 
of oxygen, combined with 1 of chlorine, or 7.0 
4- 4.5u These curious discoveries have been 
lately verified by Sur H. Davy. The other 
perchlorates are not known. 

Before leaving the adds of chlorine, we 
shall describe the ingenious method employ- 
ed by Mr Wheeler to procure chloric add 
from the chlorate of potash. He mixed a 
warm solution of this salt with one of fluo- 
silidc add. He kept the itiixture moderatdy 
hot for a few minutes, and to Insure the per- 
fect deoomposidon of the salt, added a slight 
excess of the add. Aqueous solution of am- 
monia will show, by the separation of silica, 
whether any of the fluosilidc add be left after 



ACID 



73 



NITRIC. 



dMteonpontimioftiieclilonila Unit wo 
can effect its complete decompontion. The 
miztura becomes turbid, and fluduUcate of 
potash is precipitated abundantly in the fionn 
of a gelatinoua mass. The supernatant li- 
quid will then contain nothing but chloric 
add, contaminated with a small quantity of 
fluosilicic. This may be remoTed by the. 
cautious addition of a small quantity of so- 
lution of chlorate. Or, after filtration, the 
whole add may be neutralized by carbonate 
of baryta ; and the chlorate of that earth 
being obtained in crystals, is employed to 
procure the add, as directed by M. Gay 
Lussac 

ACID (NANCEIC). An add called by 
M. Braconnotnonceic, in honour of the town 
of Nancy, where he lives. He discovered it 
in many acescent vegetable substances; in 
sour rice ; in putrefied juice of beet-root ; in 
sour decoction of carrots, pease, &c. He 
imagines that this add is generated at the 
same time as vinegar in organic substances, 
when they become sour. It is without co- 
lour, does not crystallize, and has a very add 



He concentrates the soured juice of the 
beet-root till it become almost solid, digests 
It with alcohol, and evaporates the alcoholic 
solution to the consistence of syrup. He di- 
lutes this with water, and throws into it car- 
bonate of zinc.till it be saturated. He passes 
the liquid through a filter, and evaporates till 
a pellicle appears. The combination of the 
new add with oxide of zinc crystallizes. 
After a second crystallization, be redissolves 
it in water, poura in an excess of water of 
baryta, decomposes by sulphuric add the 
barytic salt fonned, separates the deposit by 
a Sltetp and obtains, by evaporation, the new 
add pure. 

It forma with alumina a salt resembling 
gum, and with magnesia one unalterable in 
the air, in little granular crystals soluble in 
25 parts of water at 66^ Fahr. ; with potash 
and aoda it forms uncrystalUzable salts, deli- 
quescent, and soluble in alcohol ; with lime 
and stiontia, soluble granular salts; with 
baryta, an uncrystalliiable nondeliquesoent 
salt, having the aspect of gum ; with white 
oxide of manganese, a salt which crystallizes 
in tetnhedral prisms, soluble in 12 parts of 
water at 60^ ; with oxide of zinc, a salt crys- 
tallizing in square prisms, terminated by sum- 
mits obliquely truncated, soluble in 50 parts 
of water at 66^ ; with iron, a salt crystallizing 
io slender four-sided needles, of sparing solu- 
bility, and not changing in Ihe air ; with red 
oxide of iron, a white noncrystallizing salt ; 
with oxide of tin, a salt crystallizing in wedge- 
form octahedrons; with oxide of lead, an un- 
cryatallizable salt, not deliquescent, and re- 
sembling a gum ; with black oxide of mer- 
cuiy, a very soluble salt, which crystallizes 
in needles. See AaD (PBcnc). 



ACID (NITRIC). Three p«rte of pure 
nitrate of potash, coarsely powdered*, are to 
be put into a glasa retort, with two of strong 
sulphuric add. Tins must be cautiously add- 
ed, taking care to avdd the fumes that arise. 
Join to the retort a 'tubulated recdver of 
large capadty, with an adopter interposed, 
and lute the junctures with glazier's putty- 
In the tubulure fix a glass tube, terminating 
in another large reedver, in whidi is a small 
quantity of water ; and, if you wish to collect 
the gaseous products, let a bent glass tiibe 
from this recdver communicate with a pneu- 
matic trough. Apply heat to the recdver 
by means of a sand bath. Hie firat product 
that passes into the recdver is generally red 
and fuming ; but the appearances gradually 
diminish, till the add comes over pale, and 
even colourless, if the materials used were 
dean. After this it again becomes more and 
more red and fuming, till the end of the 
operation ; and the whole mingled together 
will be of a yellow or orange colour. 

Empty the recdver, and again replace it. 
Then introduce by a small funnel, very cau- 
tiously, one part of boiling water in a slender 
stream, and continue the distillation. A small 
quantity of a weaker add will thus be ob* 
tdned, which- can be kept apart. The first 
will have a spedfic grarity of about 1.500, if 
the beat has been properly regulated, and if 
the recdver was rdfrigerated by cold water or 
ice. Add of that density, amounting to two- 
thirds of the wdght of the nitre, mdy thu» be 
procured. But conunonly the heat is pushed 
too high, whence more or less of the add is 
decomposed, and its proportion of water unit- 
ing to the remdnder, reduces its strength- 
It is not profitable to use a smaller propor- 
tion of sulphuric add, when a concentrated 
nitric is required. But when only a dilute 
add, called in commerce tuptafvHit^ is re- 
quired, then less sulphuric add will suffice^ 
provided a portion of water be added. One 
hundred parts of good nitre, sixty of strong 
sulphuric add, and twenty of water, form 
ec6nomical proportions. 

As this acid still holds in solution more or 
less dftrous gas, it is not in lact pure; it is 
therefore necessary to put it into a retort, to 
which a recdver is added, the two vessels not 
bdng luted, and to apply a very gentle heat, 
changing the recdver as soon as it is filled 
with red vapours. The nitrous gas will thus 
be expelled, and the nitric acid will remdn 
in the retort as limpid and colourless as wa- 
ter. It should be kept in a bottle seduded 
from the light, otherwise it will lose part of 
its oxygen. 

What reoodns in the retort is a bisulphate 
of potash. 

As nitric add, in a fluid state, is always 
mixed with water, different attempts have 
been made to ascertdn its strength, or the 
quantity of real add contdned in it 



ACID 74 NITRIC 

MrKirwmngaTe68astheqfiMatityofi«d ctnt, the root is 1.053; and Ibraach decade 

add in iOO of the liqiiid acid viwpeoAe gca- vp to 70, li» ivot arnut be diminlabed bf 

'vity 1.500 : Sir H. Davy's determination wee 0.008. Thus, for 60, it will become 1.051, 

91; Dr Wollaston's, as inftrred from the ex- and for 70, 1.049. Abo^e this we shall ob^ 

perimeots of Mr R. FhUlips, 75; and Mr tain a precise correspondence with ezperi- 

Dalton's corrected result from Kirwan's table ment, up to 1.500 sp. graTity, if for each 

was 68. In this state of discordance I per- successiTe decade we subtract 0.0025 from 

formed a series of experiments, with the view the last diminished root, before raising it to 

•of determining the constitution of liquid ni- the desired power, which represents the per- 

tric add, and published an account of theno, centage of liquid add. 
with some new tables, in the fourth and sixth It is established by the concurring expert- 

volumes of the Journal of Sdenoe and the ments of Sir H. DaTy and M. Gay Lussac^ 

Arts. that dry nitric acid is a compound of 3( to- 

From regular prisms of nitre I procured, Inmes of oxygen combined with one of m'tro- 

by slow distillation, with concentrated oil of gen ; of which the wdgfats are 2.5 X 1*111 

▼itriol, nitric acid ; whicfa'by' the tests of ni- ss 2.777 for the proportion of oxygen, and 

trates of silver and of baryta was found to 0.0722 for that of nitrogen ; and in 100 parts, 

be pure. Only the first portion that came of 73j> of the former -f- 26| of the latter, 

over was employed for the experiments. It But nitrogen combines with several infierior 

was neariy colourless, and had a spedfic gra- proportions of oxygen, which are all multiples 

vity of 1.500. A redistiUed and colourless of its prime equivalent l.O ; and the present 

futric add, prepared in London, was also compound is exactly represented by making 

used For experiments of verification, in esti- one prime of nitrogen =s 1.75, and five of 

mating the quantity of dry add in liquid add oxygen = 5.0 : whence the add prime is the 

of a known density. sum of these two numbers, or 6.75. Now 

The above add of 1.500 being mixed in this result, deduced from its constituents, co- 
numbered phials, with pure water, in the dif- inddes perfectly with that derived from the 
ferent proportions of 95 -|- 5^ 00 -^ 10, 80 quantity in which this add saturates definite 
•f. 20, &c I obtained, after due a^tation, quantities of the salifiable bases, potash, soda, 
and an interval of 24 hours, liquids whose lime, &c. There can be no doubt, therefore, 
spedfic gravities, at 60^ Fahrenhdt, were de- that the prime equivalent of the add is 6.75 ; 
termSned by means of an accurate balance, and as little that it consists of five parts of 
with a narrow-nccked glass globe of known oxygen, and 1.75 of nitrogen. Possessed of 
capadty. By considering the series of num- these data, we may perhaps see some reason 
hm thus obtained, I discovered the geometri- why the greatest condensation of volume, in 
4sal law whidi regulates them. The spedfic diluting strong liquid add, should take place 
grarity of dilute add, containing ten parts in with 58 of it, and 42 of water. Since 100 
the 100 of that whose density is 1.500, is parts of add of 1.500 contain, by my ex- 
1.054. Takuig this number as the root, its periments, 79.7 of dry add, therefore add of 
successive powers will give us the successive the above dilution will contain 46 dry add, 
densities, at the terms of 20, 90, 40, &c. per and 54 water ; or reducing the numbers to 
cent Thus 1.054* ss 1.1 1 1, is the spedfic % prime proportions, we have the ratio of 6.75' 
gravity correqKmding to 20 of the strong lU to 7.875, bdng that of one prime of real add 
quid add -|- 80 water; 1.054* as 1.171, is to seven primes of water. But we have seen 
that for 30 per cent of strong acid ; 1.054*- ^ that the real add prime is made up of one of 
1.234, is the spedfic gravity at 40 per cent nitrogen associated by chemical affinity with 
llie spedfic gravities are therefore a series of five of oxygen. Now imagine a figure, in 
numbers in geometrical progression, corres- which the central prime of nitrogen is sur- 
ponding to the terms of dilution, another^series rounded by five of oxygen. To the upper 
in arithmetical progression, exacdy as I had and under surface of the nitrogen let a prime 
shown in the 7th number of the Journal of of water be attached, and one also to each of 
Sdence with regard to sulphuric add. Hence, the primes of oxygen. We have thus the 
if one term be given, the whole series may seven primes distributed in the most compact 
be found. On uniting the strong add with and symmetrical manner. By this kypolhem 
water, a considerable condensation of volume we can understand, how the elements of arid 
takes place. The maximum condensation oc- and water may have such a collocation and 
curs when 58 of acid are mixed with 42 of proportion, as to give the utmost efficacy to 
water. Above Uiis point the curve of con- their reciprocal attractions, whence the maxi- 
densation has a contrary flexure ; and, tiiere- mum condensation will result A striking 
-fbre^ a small modification must be made on analogy will be found in the dilution of sul- 
the root 1.054, in order to obtain with final phuric add. 

accuracy, in the higher part of the range, the If on 56 parts by wdgfat of add of 1.500, 

numerical powere which represent the spedfic we pour cautiously 42 of water in a graduated 

gravities. The modification is, however, very measure, of which the whole occupies 100 

simple. To obtain the number for 50 per divisions, and then mix them intimately, the 



ACID 



75 



NiTRra 



tMnpenftim wWrliefipoiiiOOOtol400; rad 
•fWr eooUng to 60^ ■gaia» the ▼olume will 
be faatid only 98.65. No other proportion 
of water end ecid ceuMB the evolution of » 
miBcfa heeL When 90 perts of the itrong 
ecid era united with 10 of weter, 100 in to- 
famie become 97; end when 10 pertt of the 



eeme eeid era (oanbined wHfa 90 of weter, the 
resulting Tolume is 96w It desertes notice^ 
thet 80 of add -f 20 weter, end 30 of edd 
-f- 70 water, eech gives e dilute ecid, whose 
degree of condenietion is the seme ; nemely* 
100 meesuras become 9i.8. 



TABLE of NITRIC ACID, by Dr Um. 



teecUSc 
GnvUy. 


ioioa 


Dry add 
knioa 


GisYlty. 


Add 
InUXL 


Dry add 
inioa 


GnTity. 


liq. 
Add 
in 100. 


Dry add 

inioa 


iSpedflc 
Gravity. 


Liq. 
Add 
inioa 


Dry add 
la 100. 


1.5000 


100 


7a7oo 


1.4189 


75 


5a 775 


1.2947 


50 


39.850 


1.1403 


26 


ia925 


1.4980 


99 


7a903 


1.4147 


74 


5a978 


1.2887 


49 


39.053 


1.1345 


24 


iai28 


l.i960 


98 


7a 106 


1.4107 


73 


5ai81 


1.2826 


48 


3a256 


1.1286 


23 


ia331 


1.4940 


97 


77.309 


1.4065 


72 


57.384 


1.2765 


47 


37.459 


1.1227 


22 


17.534 


1.4910 


96 


7^512 


1.4023 


71 


56.587 


1.2705 


46 


^662 


1.1168 


21 


ia737 


1.4680 


95 


75.715 


1.3978 


70 


55.790 


1.2644 


45 


35.865 


1.1109 


20 


15.940 


1.4650 


94 


74.918 


1.<jH40 


69 


54.993 


1.2583 


44 


35.068 


1.1051 


19 


15.143 


1.4820 


93 


74.121 


1.3882 


68 


54.196 


1.2523 


43 


34271 


1.0993 


18 


14.346 


1.4790 


92 


7a324 


1.3aH3 


67 


53.399 


1.2462 


42 


3a474 


1.^935 


17 


ia549 


1.4760 


91 


72.527 


1.3783 


66 


52.602 


1.2402 


41 


3a677 


1.0878 


16 


ia752 


1.4730 


90 


71.730 


1.3732 


65 


51.805 


1.2341 


40 


31.880 


1.0821 


15 


11.955 


1.4700 


89 


7a9as 


1.3681 


64 


51.068 


1.2277 


39 


31.083 


1.0764 


14 


11.158 


1.4670 


88 


7a 136 


1.3630 


63 


50.211 


1.2212 


38 


30.286 


1.0708 


13 


10.361 


1.4640 


87 


69.339 


1.3579 


62 


4a414 


1.2148 


37 


2a499 


1.0651 


12 


a564 


1.4600 


86 


6a542 


1.3529 


61 


4a617 


1.2084 


36 


2a692 


1.0595 


a 


a767 


1.4570 


85 


67.745 


1.3477 


60 


47.820 


1.2019 


35 


27.895 


1.0540 


10 


7.970 


1.4530 


84 


6a948 


1.3427 


59 


47.023 


1.1958 


34 


27.098 


1.0485 


9 


7.173 


1.4500 


83 


66.155 


1.3376 


58 


4a226 


1.1895 


33 


2a301 


1.0430 


8 


a376 


1.4460 


82 


65.354 


1.3323 


57 


45.429 


1.1833 


32 


25.504 


1.0375 


7 


5w579 


1.4424 


81 


64.557 


1.3270 


56 


44632 


1.1770 


31 


24707 


1.0320 


6 


4.782 


L4385 


80 


6a760 


1.3216 


55 


4a835 


1.1709 


30 


2a900 


1.0267 


5 


a985 


1.4346 


79 


62.963 


1.3163 


54 


4a038 


1.1648 


29 


2ail3 


1.0212 


4 


ai88 


1.4306 


78 


6a 166 


1.3110 


53 


42.241 


1.1587 


28 


2a316 


1.0159 


3 


a39i 


1.4269 


77 61.369 
76 |6a572 


1.3056 


52 


41.4U 


1.1526 


27 


21.519 


1.0106 


2 


1.594 


1.4«28 


1.3001 


51 


40.647 


1.1465 


26 


20.722 


1.0053 


1 


a797 



Hie column of dry add shows the weight 
wliidi eny saH6eble bese would gein, by unit- 
ing with 100 perts of the liquid add of the 
ooncspending spedfic gravity. But it mey be 
proper bcra to observe, thet Sir H. Davy, in 
extending Us views reletive to the constitution 
of the dry muriates, to the nitrates, hes sug- 
gested, thet the letter when dry may be con- 
sidered as consisting, not of a dry nitric edd 
combined with the selifiable oxide, but of the 
oxygen end nitrogen of the nitric edd with 
the melel itMlf in triple union. A view of 
his raeeooing will be found under the ertide 
Salt. He regards liquid nitric edd, et its 
ntmoet density, as a compound of 1 prime of 
hydragco, 1 oi nitrogen, end 6 of oxygen. 

The strongest edd that Mr Kirwen could 
procora at 60^ was 1.5543; but Rouelle pro- 
fiessee to have obtained it of 1.58a 

Nitric aad should be of the spedfic gra- 
vity of 1.5^ or a little more, and colourless. 

Hiat of Mr Kirwan seems to heve con- 
sisted of one prime of reel edd and one of 
Tf when the suitable corrections are made; 



but no conmion chemical use requires it of 
such a strength. 

Ibe atomieni rdaiioruk^ of Add end Water 
vrere thus presented by me, in a tabular 
form, in the Journal of Sdenoe for Ja- 
nuery 1819, p. 24a 



UquldAdd 


SpiGtav. 


Atoimt 


AtOBM 


of 1.5. 


dry Add. 


M^aur. 


100 


1.5000 


100 


152 


98 


1.4960 


100 


168 


96 


1.4910 


100 


183 


94 


1.4850 


100 


200 


92 


1.4790 


100 


216 


90 


1.4730 


100 


236 


86 


1.4600 


100 


275 


84 


1.4530 


100 


294 


83ineariy. 


• • • 


100 


300 


83 


1.4500 


100 


305 


57i 


1.3340 


100 


700 


47 


1.2765 


100 


1000 



ACID 76 NITRIC. 



1.45 


240 


1.42 


248 


1.40 


247 


i.ai 


242 


l.dO 


296 


1.20 


226 


1.15 


219 



Tbe followiiig table of boilii^ poinli hat ad out of a bottle tied to the end of a loii|^ 
been given by Mr Dalton« stick, otberwiie the operator's £M!e and eyea 

Add of sp. gr. 1.50 boOa at 210^ will be endangered. If it be poured on per- 

fectly dry chiuvoal powder, it excites con^ 
bustion, with tbe emission of copious fumes. 
By boiling it with sulphur it is deoomposed* 
abd its oxygen, uniting with the sulpbur* 
forms sulphuric acid. 

Proust has ascertained, that add having 
the spedfic gravity 1.48, has no more action 
At 1.42 spedfic gravity it distils unaltered, on tin than on sand, while add somewhat 
Stronger add than that becomes weaker, and stronger or weaker acts furiously on the 
weaker add stronger, by boiling. When the metal. Now, add of 1.465, by my tablei, 
strong add is cooled down to — 60^, it con- consists of one prime of real add united with 
cretes, by slight agitation, into a mass of the two of water, constituting, it would thus ap- 
consistence of butter. pear, a peculiarly powerful combination. 

This acid is eminently corrosive, and hence Add which takes up A'A oi iu wdght 
its old name of aquafortii. Its taste is sour of marble^ freezes, according to Mr Caven- 
and acrid. It is a deadly poison when in- ^^ at — 2«. When it can dissolve yJsTrW, 
troduced into the stomach in a concentrated .^ .^ ^ ^ ^,^ to-41o.6 before 

'^u'^ ^^'^ F^^ ^"^ jJ^L con^lBtion; and when so much diluted as 

swallowed without inconvenience. It is often ^ f , i a 1 6 >a ■ ^ 

contaminated, through negligence or fVaud ^J^^ "P """"J^ TinrtSf >* congeals at-- 

in the manufacturer, vrith sulphuric and mu- f^;* The iirrt has a specific gravi^ of 

riatic adds. Nitrate of lead detects both ; or l-fpO nearly, and consuts of 1 prune of dry 

nitrate of baryta may be employed to deter- •cid-f- 7 of water; the second has a speafic 

mine the quantity of sulphuric add, and ni- gravityof 1.420, and contains exactly 1 prime 

timte of silver that of the muriatic. The lal^ of dry aad -f- 4 of water ; while the third 

ter proceeds from the crude nitre usually has a speafic gravity of 1.215, conaiAing of 

containing a quantity of common salt. ^ P"™* ^ «■»« + ^\ ?^J^^^ ^* ^ 

When it b passed through a red-hot por- ^7» ^^ ^^ ^»"d aad of 1.^ composed 

oelain tube, it is resolved into oxygen and »» * P"™« of vrater-f- 1 of dry aad, poa- 

nitrogen, in the proportion above stated. It m«cs the greatest power of resisting the in. 

retains its oxygen with Uttle force, so thet it ^^^^ce of temperature to change its state, 

is decomposed by aU combustible bodies. ** requires the maximum heat to IxmI it. 

Brought into contact witfi hydrogen gas at ''«»"* '* /»«^» unchanged ; and die maxi- 

a high temperature, a violent detonation eiv- ™"™ «>*° *« ^^ >•• congelatwn. 
sues; so that this must not be done without The colour of the aad is affected by tbe 

great aiution. It inflames essential oils, as quantity of nitric oxide it holds, and Su- H. 

those of turpenUne and doves, when sudden- ^^^ *><» JP^e^ «* **»« foUowing table of pro- 

ly poured on them ; but, to perform this ex- portions answenng to its different hues, 
periment with safety, the add must be pour- 



COLOUB. 


• RfiAL AcDD. 


NiTBic Oxide. 


Wateb. 


Pale yellow, 


90.5 


1.2 


as 


Bright yellow. 


8a94 


2.96 


a 10 


Baik orange, 


86.84 


5.56 


7,6 


Light olive^ 


86.0 


6.45 


7.55 


Dark olive. 


85.4 


7.1 


7.5 


Bright green, 


84.8 


7.76 


7.44 


Blue green. 


84.6 


a 


7.4 



But these ooloun are not exact indications tals ; in medidne as a tonic, as also in fbnn 

of the state of the add, for an addition of of vapour to destroy contagion. For the 

water will change the colour into one lower purposes of the arts it is commonly used in 

in the scale, so that a considerable portion of a diluted state, and contaminated vrith the 

vrater will change the dark orange to* a blue- sulphuric and muriatic adds, by the name of 

green. agw^oriU. Two kinds are found in the 

Nitric add is of considerable use in the shops— one called iltmbie aquafortis, which ia 

arts. It is employed for etching on copper ; about half the strength of nitric acid ; the 

as a solvent of tin, to. form with that metal a other simply aquafortit, which is half the 

mordant for some of the finest dyes ; in me- strength of Uie double, 
tallurgy and assayings in various chemical A compound made by mixing two parts of 

processes, on account of the fadlity with the nitric add vrith one of muriatic, known 

which it parts with oxygen and dissolves me- formerly by the name of aqua regia, and now 



ACID 



77 



NITBIC. 



bj that of nkro'mmiatie aeid, bat the pro- 
perty of diasolviiig gold and platina. On 
nuxing the two aods, beat is given out, an 
cffisrveacenoe takes places and the mixture 
aoquires an onnge colour. This is likewise 
made hy adding gradually to an ounqe of 
powdered muriate of ammonia four ounces 
of double aquafortis, and keeping the mix- 
ture in s sand heat till the salt is dissolved; 
taking care to avoid the fumes, as the vessel 
must be left open ; or by distilling nitric add 
with an equal weight, or rather mote^ of 
common salt. 

On this subject we are indebted to Sir H. 
Davy for some excellent observations, pub- 
lished by him in the first volume of the Joui^ 
nal of Sdencck If strong nUrtni$ acid, satu- 
lated with nitrous gas, be mixed with a satu« 
fated solution of muriatic add gas, no other 
efilect is produced than might be expected 
fiom the action of nitrous acid of the same 
strength on an equal quantity of water ; and 
the mixed add so formed has no power of 
action on gold or platina. Again, if mu- 
riatic add gas, and nitrous gas, in equal 
volumes, be mixed together over mercury, 
and half s volume of oxygen be added, the 
immediate condensation will be no more than 
might be expected from the formation of 
nitroas add gas. And when this is decom- 
posed, or absorbed by the mercury, the mu- 
riatic acid gas is found unaltered, mited with 
a certain portion of nitrous ga& 

It appears then that jutrous add, and mu- 
riatic add gas, have no chemical action on 
eadi other. If eolouriest nitric add and mu- 
riatic acid of commerce be mixed together, 
the mixture immediately becomes yellow, and 
gains the power of dissolving gold and plati- 
num. If it be gently heated, pure chlorine 
arises from it, and the colour becomes deeper. 
If the heat be longer continued, chlorine still 
liaes, but mixed with nitrous add ga& When 
the process has been very long continued, till 
the colour becomes very deep, no more chlo- 
rine can be procured, and it loses its power of 
acting upon platioum and gold. It is now 
nknna and muriatic acids. It appears then 
from these observations, which have been very 
often reputed, tliat nitro-muriaUc add owes 
its peculiar properties to a mutual decompo- 
sition of the nitric and muriatic adds ; and 
that water, chlorine^ and nitrous add gas, are 
the results. Though nitrous gas axid chlo- 
rine have no action on each other when per* 
lectly dry, yet if water be present there is an 
immediate decomposition, and nitrous add 
and muriatic add are formed. 118 paYts of 
strong liquid nitric add bdng decomposed in 
this case, yield 67 of chlorine. A^ua regia 
does not oxidise gold and platina : it merely 
causes thdr combination with chlorine. 

A bath made of nitro-muriatic add, dilut- 
ed so much as to taste no sourer than vine- 
gar, or of such a strength as to prick the skin 



a little altar being exposed to it for twenty 
minutes or half an hour, has been introducMl 
by Dr Scott of Bombay as a remedy in chro- 
nic siphylis, a variety of ulcers and diseasea 
of the skin, chronic hepatitis, bilious diaposU 
tions, general debility, and languor. He coo* 
aiders every trial as quite incondusive wheret 
a ptyalism, some affection of the gujibs, or 
some very evident constitutional e^ect, has- 
not arisen from it. The internal use of thei 
same add has been recommended to be con-« 
joined with that of the partial or general 

With the different bases the nitric add 
forms nitrates. 

Nitrate of baryta, when perfectly pure^ is 
in regular octa^lral crystals, though it is. 
sometimes obtained in small shining scales. 
It may be prepared by uniting baryta direct- 
ly wi^ nitric acid, or by decomposing tho 
carbonate or sulphuret of baryta with this, 
add. Exposed to heat it decrepitates, and 
at length gives out its add, which is decom- 
posed ; but if the heat be ui^ged too far, the 
baryta is apt to vitrify with the earth of tbfr 
crucible. It is soluble in 12 parts of oold» 
and 3 or 4 of boiling water. It is said to 
exist in some mineral waters. It consists of- 
6.75 add-H 9.75 base. 

Nitrate of potash ii the salt well known 
by the name of nitre or taUpetre. It is found 
ready formed in the East Indies, in Spain, in- 
the kingdom of Naples, and elsewhere^ in 
conaidenble quantities : but nitrate of lime is. 
still more abundant. Far the greater part of 
the nitrate made use of is produced by a com- 
bination of drcumstances which tend to conw 
pose and condense nitric add. This add ap- 
pean to be produced in all situations, where' 
animal matters are completely decomposed 
with access of air, and of proper substanoea 
with which it can readily combine. Grounds 
frequently trodden by cattle, and impregnated 
with their excrements, or the walls of inbsF- 
bited places, where putrid animal vapours 
abound, such as slaughter-houses, drains, or 
the like, afford nitre by long exposure to the 
air. Artificial nitre beds are made by an at- 
tention to the drcumstances in which this salt 
is produced by nature. Dry ditches are dug^ 
and covered with sheds, open at the sides, to 
keep off the rain ; these are filled with animal 
substan ce s ou ch ss dung, or .other excre- 
ments, with the remains of vegetables, and 
old mortar, or other loose calcareous earth ; 
this substance bdng found to be the best and 
most convenient receptacle for the add to 
combine with. Occasional watering, and 
turning up from time to time^ are necessary 
to aocderate the process, and increase th^ 
surfaces to which the dr may apply ; but too 
much moisture is burtfuL When a certain 
portion of nitrate is formed, the process ap- 
pears to go on more quickly ; but a certdn 
quantity stops it altogether, and after this. 



ACID 78 NITBia 

tion tiM mitariah will 90 on to f arniilt ptttnii» with dTednl •ommiti. Iti tarte k 
man, if what is fortncd be extracted by lixi- peneCrathig ; but the cold produced by 
viation. After a suocesaioii of many months, placing the salt to dissolre in the mouth, is 
more or less, according to the management such as to predominate over the real taste at 
ef the operation, in which the action ^ a re- 6rst Seven parts of water dissolve two of 
gttlar current oif fresh air is of the greatest nitre, at the temperature of 60^ ; but boiling 
importance^ nitre is found in the mass. If water dissolves its own weight. 1 00 parts of 
the beds contained much vegetable matter, a alcohol, at a heat of 176^, disserve only 2.9. 
eonadersble poiticm of the nitrous salt will Itsconstituentsarenitricacid&Td «*f- potash 0. 
be common saltpetre; but if otherwise^ the On being exposed to a gentle heat, nitre 
add will, for the most pert, be combined fuses; and in this state bdng poured into 
with the calcareous earth* moulds, so as to form little round cakes, or 
To extract the saltpetre from the mass of balls, it is called $al prundia, or ciysitU mi- 
earthy matter, a number of large casks >are turoL 

prepared, with a cock at the bottom of each, This salt powerfully promotes the 00m- 

and a quantity of straw within, to prevent iu bustion of inflammable substances. Two or 

being stopped up. Into these the matter is three parts mixed with one of charcoal, and- 

put, together with wood-ashes, either strewed set on fire^ bum rapidly ; azote and caibonic 

at top, or added during the filling. Boiling add gas are given out ; and a small portion 

water is then poured on, and sufitored to stand of the latter is retained by the alkaline resi- 

ibr some time; after which it is drawn ofl^ doum, which was formerly ealied cljfssus of* 

and other water added in the same manner, nitre. Three parts of nitre, two of subcar-> 

as long as any saline matter can be thus ex- bonate of potash, and one of sulphur, mixed 

tracted. The weak brine is heated, and pass- together in a warm mortar, form the /u /m»- 

ed through other tubs, until it becomes of mUing powder; a small quantity of wbicby 

considerable strength. It is then carried to laid on a fire shovel, and held fus&r the fire 

the boiler, and contains nitre and other salts ; till it b^ns to mdt, explodes with a loud 

the chief of which is common culinary salt^ sharp noise. Mixed with sulphur and char- 

and sometimes muriate of magnesia. It is coal it forms gunpowder. See Gonpowbcr. 
the property of nitre to be much more soluble Three parts of nitre^ one of sulphur, and 

in hot than cold water; but common salt is one of fine saw-dust, well mixed, constitute 

very nearly as soluble in cold as in hot water, what is called the powder of fusion. If a 

Whenever, therefiite, the eviqioration is car- bit of base copper- be folded up and covered 

ried by lioiling to a certain point,, much of with this powder in a walnut-shdl, and the 

the common salt will fall to the bottom, for powder be set on fire with a lighted paper, 

want of water to hold it in solution, though it will detonate rapidly, and fuse the metal 

the nitre will remain suspended by virtue of into a globule of sulphuret without burning 

the heat. The common salt thus separated the shelL 

IS taken out with a perforated ladle, and a Silex, alumina, and baryta, decompose 

small quantity* of the fluid is cooled, from this salt in a high temperature by uniting 

time to time, that its concentration may be with its base. The alumina will eflfect this 

known by the nitre which crystallises in it even after it has been made into pottery. 
When the fluid is suffidently evaporated, it The uses of nitre are various. Beside 

is taken out and cooled, and great part of the those already indicated, it enters into the 

nitre separates in crystals ; while the remain- composition of fluxes, and is extensively em- 

ing common salt continues dissolved, because ployed in metallurgy ; it serves to promote 

equally soluble in cold and in hot water, the combustion of sulphur in fabricating ita 

Subsequent evaporation of the residue will add; it is used in the art of dydng; it is 

separate more nitre in the same manner. By added to common salt for preserving meat, 

the suggestion of Lavoisier, a much simpler to which it gives a red hue ; it is mi ingre- 

plan was adopted ; redudng the crude nitre dient in some frigorific mixtures ; and it is 

to powder, and washing it twice with water, prescribed in medidne, as cooling, febriftige. 

This nitre,, which is called nitre of the first and diuretic ; and some have recommended 

boiling, contains some common salt; fitnn it mixed with vinegar as a very powerful 

which it may be purified by solution in a remedy for the sea scurvy, 
small quantity of water, and subsequent eva- Nitrate of soda, formerly called cubic or 

poration ; for the crystals thus obtained are quadrangular nitre, approaches in its proper- 

much less contaminated with common salt ties to the nitrate of potash ; but diflTers horn. 

than before; because the proportion of water it in bdng somewhat more soluble in cold 

is so much larger, with respect \o the small water, though less in hot, which takes up 

quantity contained by the nitre, that very lit- little more than its own weight ; in bdng 

tie €f it will crystallize. For nice purposes, inclined to attract moisture from the atmo»- 

the solution and crystallization of nitre are phere ; and in crystallizing in rhombs, or 

repeated four dmes. The crystab of nitre are rhomboidal prisms. It may be prepared by ' 

usually of the form of six-sided flattened satimting aoda with the nitric add ; by pre- 



ACID 79 NITRIC. 



_ nitrie lokitioai of At bcCbW ot ot explodiDi^ aod htuig totally deodmpoMd^ 

mi the cnthsy except Imi7«b> by toda; by at tbe tempenture of 600^ ; wbeiice it ae-t 

Uzmatiiig and cryatalliang tba rcuduum of quired tbe name of niirum flammam. The 

rftff TTMi" aalt diadUed with threc4burtfa8 iti reedioat mode of preparing it is by adding 

wciglit of nitric add ; or by saturating tbe carbonate of ammonia to dilute nitric add 

mociber waters of nitre with soda, instead of till saturation takes p]ao& If this salutioa 

pgteah. be evaporated in a heat between 70^ and 

Thia salt has been considered as useless ; 100^, and tbe eraporation not cairied toa 

bst ptofeascr Pkoust says, that five perts of ftr, it crysteUiaes in hezaedral prisms termi** 

ity with one of charcoal and cue of sulphur, nating in very acute pyramids: if the heat. 

will bum three times as long as common rise to 212^, it will afibrd, on ooc^g, long 

powder, so as to form an economical com- fibrous silky crystals: if the evaporation be 

poaitioo lor fire-works. It ooosists of 6.75 carried so ftr as for the salt to concrete im- 

add 4- 4 soda. mediately on a glass rod by cooling, it will 



Nitrate of strontia may be obtained in the form a compact ^niass. According to Sir 
manner aa that of baryta, with which U. Davy, these differ but Uttle from each 



it agreea in the shape of itt crystals, and most other, except in the water tbey contain, their 

of ite properties. It is much more soluble^ component parte being as follows : 
howcverv requiring but four or five parte of 

water according to Vauquelin, and only an ?SS2*'?««!S"JSs-T<^ SlM 

efoal weight according to Mr Henry. BoiU coBpact S ^"^ 674^ ^ ClSiS I &7 
ia% ymbet diasolves iwariy twice as much aa 

eold. Applied to the wick of a candle^ or All these are completely ddiquesoent, but 

added to boraing alcohol, it gives adeep red they diffhr a little ii» solubility. Alcohol at 

to die fiamew On this account it is 176^ dissolves nearly 90.9 of ite own wdgbt. 



oaelnl in the art of pyrotecfany. It coosiste When dried as much as possible without 

of d.75 add -^ 6.5 strontia. decomposition, it oonasto of 6.75 add -^ 

Nitrate of limc^ the ealeartaut nitr§ of 8.125 ammonia -f- 1.125 water. 
oUer writers, abounds in the mortar of old The chief use of this salt is for affording 
buildings, particulariy those that have been nitrous oiide on bring decomposed by heat, 
much expoKd to animal effluvia, or pro* See NinoaEN (OxiOB of). 
cesaes in wfaidi asote is set free. Hence it Nitrate of magnesia, magnetum nUre, crys- 
abowndE in nitre beds, as was observed when tallixes in four-^ided rhomboidal prisms, with- 
treating of the nitrate of potash. It may oblique or truncated summits, and sometimes 
also be prepared artificially, by pouring dilute in bundles of small needles. Ite taste is bit- 
nitric add on carbonate of limeu If the ter, and veryrimilartotfaatof nitrsteof lime. 



be boiled down to a syrupy consia^ but less pungent. It is furible, and deoom^ 

tence, and exposed in a cool place, it cry^ posable by heat, giring out first a little oxy- 

talliaes in long prisms, resembling bundles gen gas, Uien nitrous oxide, and lastly nitric 

of needles diverging from a centre. These acid. It deliquesces slowly. It is soluble 



soluble according to Henry, in an equal in an equal weight of cold water, and in but 

vreigbt of boiling water, and twice limr little more of hot, so that it is scarcely crys- 

weight of cold ; soon detiquesce on exposure tsllizable but by spontaneous evaporation. 

to the air, and are decomposed at a red heat. The two preceding spedes are capable of 



Feurcroy says, that cold water dissolves four combining into a triple salt, an ammoniaoo- 

times ite wdgfat, and that ite own water of raagnesian nitrate, dther by uniting the two 

crystallization is suffident to dissolve it at a in solution, or by a partial decomposition of 

bdling beat. It is likewise soluble in less dther by means of tbe base of the other, 

than ite wcigbt of alcohol. By evaporating This is slightiy inflammable when suddenly 

die aqueous solution to dryness, continuing heated; and by a lower heat is decomposed, 

the beat till the nhrato fuses, keeping it in giring out oxygen, azote, more water than it 

this stale fire or ten minutes, and then pour- contained nitrous oxide, and nitric add. Tbe 

ing It into an iron pot preriousiy heated, we residuuro is pure magnesia. It is disposed 

obtain Baldwin ^ phoaphonu. Ibis, which to attract moisture from the air, but is much 

is t i wb ap s more properly nitrau of Unuy less deliquescent than cither of the salto that 

being broken to pieces, and kept in a phial compose it, and requires eleven parte of water 

dosdy stopped, wfll emit a beautiful white at 60^ to dissolve it. Boiling water takes up 

light in the dark, afWr having been exposed more^ so that it will crystallize by cooling. 

ioaae time to the rays of the sun. At pre- It consiste of 78 parte dP nitrate of magnesiay 

Bcnt no ttse is made of this salt, except for and 22 of nitrate of ammonia, 
drying some of the gsses by attracting their From the actirity of the nitric acid as a 

moisture; but it might be employed instead solvent of earths in analysis, tbe nitrate of 

of tbe nitnte of potadi for mamifiirtaiing i^ucina u better known than any other of 

aq uafi wtia. the salte of this new earth. Ite form is 

'. Nitrate of ammonin poss^nes the property either pulvcralent, or a tenadous or ductile 



I 



ACID 80 KXTBIC, OXYGENIZED. 



Its taito is at fifst ncduvine, mud It is the sanie add, aooofding |io M. Gay 
afterwards astriogenti It grows soft by ex- Liutac, which is produced on leaving for a 
posure to heat, soon melts, its add is decom- long time a strong solution of potash in con- 
posed into oiygen and asote, and its base tact with deutoxide of axote. At the end of 
alooe is left behind. It is very soluble^ and three months he found that 100 parts of 
very deliquescent. deutoxide of aiote were reduced to 25 of 

Nitrate, or rather superaitrate, of alumina protoxide of azoie^ and that crystals of hypo- 

crystallizes, though with difficulty, in thin, nitrite (perftttriu) were formed, 

soft, pliable flakes. It is of an austere and Sypimiirout add (called f}emitrou$ by the 

add taste, and reddens blue v^etable colours. FVench chemists), cannot be insulated. As 

It may be formed by dissolving in diluted soon as we lay hold, by an add, of the pot- 

nttiic add, with the assistance of heat, fresh ash with which it is associated, it is trans* 

piedpitated alumina, well washed but not formed into deutoxide of azote^ which is di»- 

dried. It is deliquescent, and soluble in a engaged, and into nitrous or nitric add, which 

very small portion of water. Alcohol dis-- remains in solution. 

solves its own wdght. It is eaaUy deoom- ACID (NITRO-LEUCIC). Leucine ia 

posed by heat capable of uniting to nitric add, and forming 

Nitrate of ziroonia was first discovered by a compound, which M. Braoonnot has called 

Klaproth, and has since been examined by the nitro-leudc add. Whoi we disserve 

Guyton-Morveau and Vauquelin. Its crys- leucine in nitric add, and evaporate the so- 

tals are small, capillary, sUky needles. Its lution to a certain point, it passes into a crys- 

taste is astringent. It is easily decomposed talline mass, without any disengagement of 

by fire^ very soluble in water, and deliques- nilarous vapour, or of any gaseous matter : 

e&oL It may be prepaaed by dissolving zir- If we press this mass between blotting paper,- 

oonia in strong nitric add ; but, like the pre- and redissolve it in water, we shall obtain 

ceding species, the add is always in excess. from this, by oonoentration, fine, divergent^ 

Nitrate of yttria may be .prepared in a si- and nearly coloujiess needles. These con-* 

mikr manner. Its taste is sweetish and stitute the new add. It unites to the bases 

astringent. It is scarcely to' be obtained in forming salts, which fuse on red-hot coals, 

crystals ; and if it be evaporated by too The nitro4eucates of lime and magnesia are 

strong a heat, the salt becomes soft like unalterable in the air. 

honey, and on cooling concretes into a stony ACID(NITRO-SACCHARIC). Wheo 

mass. See Salt. we heat- the tugar of gelatin with nitric add, 

ACID (NITROUS). This add is ob- it dissolves without any apparoit disengag»- 
tained by exposing nitrate of lead to heat in ment of gas ; and if we evaporate this solution 
a glass retort Pure nilroue add comes over to a proper degree, it forms, on cooling, a 
in the form of an orange'<:oIoured liquid, crystalline mass. On pressing this mass be- 
lt is so volatile as to boil at the temperature tween the folds of bl<^ng papa, and recrys- 
of 82°. Its spedfic gravity is 1.450. When tailizing them, we obtain 'beautiful prisms, 
mixed with water it is decomposed, and ni- colourless^ transparent, and slightly striated, 
trous gas is disengaged, occasioning eflTerves- Tliese crystals are very different from those 
oence. It is composed of one volume of which serve to produce them ; constitute, ao- 
oxygen united with two of nitrous gas. It cording to M. Braconnot, a true add, which 
therefore consists ultimatdy, by wo^t, of results from the combination oftbe nitric add 
1.75 nitrogen -^ 4 oxygen ; by measure^ of itself, with the sweet matter of which the first 
2 oxygen 4- 1 nitrogen. The various 00- crystals are formed. M. Tbenard concdvea 
loured adds of nitre are not nitrou* adds, but it is the nitrous add which is present 
nitric add Impregnated with nitrous gas, the Nitro-saccharic acid has a taste similar to 
deutoxide of nitrogen or azote. (See the thatof the tartaric; only it is a little sweetish, 
preceding table of Sir H. Davy, concerning Exposed to the fire in a capsule, it froths 
the coloured add). much, and is decomposed 'with the diffusion 

ACID(HYPONITROUS). Itappean, ofa pungent smell. Thrown on burning coals 

from the experiments of M. Gay Lussac, it acts like saltpetre. It produces no change 

that there exists a third add, formed of 100 in saline solutions. Finally, it combines with 

azote and 150 oxygen. When into a test the bases, and gives birth to salts which pos- 

tube filled with mercury, we pass up from sees peculiar properties. For example,.tbe salt- 

500 to 600 volumes of deutoxide of azote, a which it forms with lime is not deliquescent, 

little alkaline water, and lOOparts of oxygen and is very little soluble in strong alcohol 

gas, we obtain an absorption of 500, pro-.' Huit which it produces with the oxide of lead 

ceeding from the condensation of the 100. detonates to a certain degree by the action of 

parts of oxygen with 400 of deutoxide of heat Ann, de Chitnie et de Phys* xiii. 113. 

azote. Now these 400 parts are composed of ACID (NITRIC, OXYGENIZED). 

200 axote and 200 oxygen ; consequently the In our general remarks on aridity, we have 

new add is composed of azote and oxygen, in . described M. Tbenard*s newly discovered me- 

the ratio of 100 to 150, as we have said above, thod of oxygenizing the liquid adds. The 



ACID 



81 



OLEIC. 



€nt that be examiiied was the oombinatioii 
of nitric add and oxjgen. When tbe per- 
oxide of barium, prepared by saturating ba- 
ryta with oxygen, is moistoiedy it fidb to 
ponrder without much increase of tempera- 
tare^ If in this state it be mixed with seven 
or ei|^t times its weight of water, and dilute 
nitric acid be gradually poured upon it, it 
disaolTes gradually by agitation, without the 
evolution of any gas. The solution is neu- 
tral, or has no action on turnsole or turmeric. 
When we add to this solution the requisite 
quantity of sulphuric add, a copious predpi- 
tate of sulphate of baryta fklls, and the filtered 
liquor is merely water, holding in solution oxy- 
gcniaed nitric add. Hiis add is liquid and 
coloariesB ; it strongly reddens turnsole, and 
resemblca in all its properties nitric add. 

When hea^ it immediately begins to dis- 
diarge oxygen ; but its decomposition is never 
complete, unleas it be kept bdling for some 
time. The only method which M. Thenard 
Ibund successful for concentrating it, was to 
place it in a capsule, under the reodver of an 
air-pump^ along with another capsule fiiii of 
lime, and to exhaust the recdver. By this 
means he obtdned an add suflSdently con- 
centrated to give out eleven times its bulk of 



lliis add combines very well with baryta, 
potash, soda, ammonia, and neutralizes them. 
When crystallization commences in the liquid, 
by even a spontaneous evaporation, these salts 
are instantly decomposed. Hie exhausted re- 
odver also decomposes them. Theoxygenized 
nitrates, when changed into common nitrates, 
do not change the state cS their neutrdization* 
Strong solution of potash poured into their 
solntions decomposes them. 

Oxygenized nitric add does not act on 
gold ; but it dissolves all the metals which 
tfaiie common add acts on, and when it is not 
loo concentrated, it dissolves them without 
cAervescence. Deutoxide or peroxide of ba- 
rium contdns just double the proportion of 
oxygen that its protoxide does. But M. 
Hienard says, that the baryta obtdned from 
the nitrate by ignition contdns always a little 
of tbe peroxide. When oxygenized nitric 
add is poured upon oxide of silver, a strong 
effervescence takes place, owing to the dis- 
engagement of oxygen. One portion of the 
oxide of silver is dissolved, the other is re- 
duced at first, and then dissolves likewise, 
provided the quantity of add be suffident. 
Tbe solution being completed, if we add pot- 
aafa to it, by little and little, a new efferves- 
cence takes place, and a dark violet predpi- 
tate fidh ; at least this is always the colour 
of the firrt deposit. It is insoluble in am- 
monia, and, according to dl appearsnce, is a 
protoxide of nlver. 

As soon as we plunge a tube contdning 
oride of diver into a solution of oxygenized 
mtiatc of potash, a vident effervescence takes 



place, the oxide is reduced, the silver pred- 
pitates, the whole oxygen of the oxygenized 
nitrate is disengaged at the same time with 
that of the odde; and the solution, which 
contdns merdy common nitrate of potash, 
remdns neutral, if it was so at first But 
the most unaccountable phenomenon is tiie 
following :-*If silver, in a state of extreme 
diridon (fine filings), be put into the oxy- 
genized nitrate, or oxygenized muriate of pot- 
ash, the whole oxygen is immediately dis- 
engaged. The silver itself is not attackml^ 
and the sdt remdns neutral as before. ■ Iron, 
dnc, copper, bismuth, lead, and platinum, 
likewise poaaess this property of separating 
the oxygen of the oxygenized nitrate. Iron 
and zinc are oxidized, and at tbe same time 
occsdcm the evolution of oxygen. The other 
metals are not sensibly oxidized. They were 
all employed in the state of filings. Gold 
scarcely acts. The peroxides of manganese 
and of lead decompose these oxym'trates. A 
very smdl quantity of these oxides, in powder, 
is sufficient to drive off the whole oxygen 
from the saline solution. Tlie effervescence 
is livdy. The peroxide of manganese un- 
dergoes no dteration. 

Though nitric add itself baa no action on 
the peroudes of lead and manganese^ the 
oxygenized add dissolves both of them minh 
the greatest Ikcility. The solution is accom- 
panied by a great disengagement of oxygen 
gas. The effect of diver, he thinks, may pr»> 
babiy be ascribed to voltdc deetridty. 

The remarks appended to our account of 
M. T1ienard*s oxygenized muriatic add are 
equally applicable to the nitric ; but tbe phe- 
nomena are too curious to be omitted in a 
work of the present kind. 

ACID (OLEIC). When potash and hog's 
lard are saponified, the margarate of the d- 
kali separates in the form of a pearly-looking 
solid, while the fluid fat remdns in solution, 
combined with the potash. When the alkali 
is separated by tartaric acid, tbe oQy prind- 
pie of fat is obtdned, which M. Chevreul 
purifies by saponifying it agdn and again, 
recovering it two or three times ; by which 
means the whole of the nuurgarine is sepa- 
rated. As this oil has the property of sa- 
turating bases, and fionning neutral com- 
pounds, he has cdled it oldc add. In his 
sixth memoir, he gives the foUowing table of 
results :— 

100 Oldc add of human fiit 
Saturate Baryta, Strontia, Lead, 

2&00 19.41 B2.48 

100 Oldc acid of sheep fat 

26.77 19.38 81.81 

100 Oldc add of ox fiit 

2a93 19.41 81.81 

100 Oldc add of goose fat 

26.77 19.38 81.34 

100 Oldc add of hog ikt 

27.00 29138 81.80 

F 



ACID ^ OXALIC 

Oleic acid it tm oily fluid without taste quantity of oxalic add furnished by Tegetable 
and smeU. Its specific gravity is 0.914*. It matters thus treated is proportionable to their 
is generally soluUe in its own weight of boil- nutritive quality, and particularly that, from 
ing alcohol, of the specific gravity of 0. 7952 ; cotton, he could not obtain any sensible quan- 
bttt some of the varieties are still more solu- tity, Deyeuz, having cut with sdssars the 
blew 100 of the oleic acid s a tm at e 16w58 of hairs of the chick pea, found they gave out 
potash, 10.11 of soda, 7.52 of magnesia, an add liquor, whidi, on examination, proved 
14^83 of anc, and 13.93 peroxide of copper, to be an aqueous solution of pure oxalic add. 
M. Chevreul*s experiments have finally in- Proust, and other chemists, had before ob- 
duoed him to adopt the quantities of 100 add served, that the shoes of persons walking 
to 27 baryta, as the most correct; whence through a field of chick peas were corroded* 
calling baryta 9.75^ we have the equivalent Brsconnot has lately shown, that the crust- 
prime of oleic add s= 36.0. aceous lichens^ such as }}€HtLiana comMunu% 
ACID (OXALIC). This add may be urceolaria scrupom, itidium coraliinunh pa* 
obtained finom sugar in the following way :— leUaria /artareo, veraota rubra, hematommOf 
To six ounces of nitric add in a stoppered baomiceserieetorumfMquamarialenHgeratpla' 
retort, add, by degrees, one ounce of lump codium radiotwUf ochroleucumt psora can- 
sugar coarsely powdered. A gentle heat may dida, contain nearly one-half their wdgfat of 
be applied during the solution, and nitric oxalate of lime ; a substance which is to these 
oxide will be evolved in abundance. When plants what carbonate of lime is to corallines^ 
the whole of the sugar is dissolved, distil off and phosphate of lime to animal bones. Hum- 
9 part of the acid, till what remains in the boldt says, these are the lichens by which the 
letort has a syrupy consistence ; and this will earth void of vegetation in the north of Peru 
form regular crystali^ amounting to 58 parts b^^ to .be covered : by thdr means vegeta- 
Irom I^ of sugar. These crystals must be tion seems to commence on the barren sur- 
dissolved in water, recrystalliied, and dried face of rocks. By the successive action of 
on blotting paper. solution of carbonate of soda, aided by a boil- 
Many other substances afford the oxalic ing heat, the Oxalate of lime in these planta 
add when treated by distillation with the ni- is converted into a carbonate, while oxalate 
trie Bergman procured it firom honey, gum- of soda remains dissolved, 
arable, alcohol, and the calculous coocre- M. Vauquelin, by treating pectic add with 
tions in the kidneys and bladders of animals, potash in a crudble, converted it into oxalate 
Scheele and Hennbstadt from sugar of milk, of potash. This production of oxalic add 
Scheele from a sweet matter contained in fat suggested to M. Gay Lussac the followiqg 
<h1b, and also from the uncrystallizable part line of experiments :— Cotton heated below 
of the juice of lemons. Hennbstadt from redness with five times its wdght of causdc 
the add of cherries, and the acid of tartar, potash and a little water, was converted part- 
.Goettling from beech wood. Kohl from the ly into oxalate of potash, as was shown by 
residuum in the disdllation of ardent spirits, supersaturating with nitric add, and testing 
Westrumb not only from the crystallised with nitrates of lead and lime. Wood saw- 
adds of currants, cherries, dtrons, raspber- dust, with the same treatment, gave the same 
ries, but also from the saccharine matters of result So did sugar, starch, gum, and sugar 
these fruits, and from the uncrystalliaable of milk, with the disengagement of hydrogen, 
parte of the add juices. Hoflboann from the The most remarkable transformation is that 
juice of the barberry; and BerthoUet from of tartaric into oxalic acid by potash, at a 
•ilk, hair, tendons, wool ; also from other temperature not exceeding 400^ F. 
animal substances, especially from the coa- Qtric and mucic adds produced also much 
gulum of blood, whites of eggs, and likewise oxalic add, as did also lithic add. Silk and 
fitm the amylaceous and glutinous parts of gelatin gave a similar result Indigo gave 
flour. M. BerthoUet observes, that the quan- no oxalic add. Soda may be used instead 
tity of the oxalic add obtained by treating of potash, but the carbonated alkali will not 
wool with nitric add was very considerable, answer. 

being above half the wdght of the wool em- From the general phenomena it may. be 

ployed. He mentions a difference which he concluded, that a vegetable substence^ heated 

observed between animal and vegetable sub- moderately with potash, gives oxalic add ; 

stances thus treated with nitric add, namely, but when more strongly heated, carbonic 

that the former yielded, beside ammonia, a acid. 

large quantity of an oil which the nitric add Tarter may be very elegantly transformed 

could not decompose ; whereas the oily parts into oxalate of potassa, by dissolring the 

of v^etables were totally destroyed by the rough tartar in water with a proper quantity 

action of this add ; and he remarks, that in of potash or soda, and making the solution 

this instance the glutinous part of fiour re- pass by means of a pump, in a continual cur- 

sembled animal substances, whereas the amy- rent, through a thick tube of iron or bronxe, 

laceous part of the flour retained its vegeta- heated to 400^ or 450" F. Hie pressure 

bl« properties. He further remarks, that the need not be more than 25 atmospheiesi for 



ACID 03 OXALIC. 

•o gM wiU be dheugoge^ A val^e b to be Dr Fjrout't ranilts (PfaiL Tnuie. I8S7) 

pboed at the opposite extremity to tbet at agree with the above, 

which the aolvtion enteni and charged with Oxalic add acts as a Tiolent poison when 

■afficieDt wei|^t to obtain this pressure; it swallowed in the quantity of two or three 

wiD then be opened only by the pressure drschms; and several fatal accidents have 

exerted fay the injection pump. Less than a lately occurred in London, in consequence of 

prioM proportion of potassa for a proportion its being improperly sold instead cf Epsom 

of nctttnl tartar will be necessary. salts. Its vulgar name of sslts, under which 

Oxalic add crystallises in quadrilateral the add is bought for the purpose of whiten- 
prismst the sides of which are alternately log boot-tops, occasions these lamentable mis- 
broad and narrow, and summits dTedral ; otf takes. But the powerfully add taste of the 
if crystallised rspidly, in small im^lar ne^ latter substance, jdned to its prismatic or 
dlo. Tbcy are e£Borescent in dry air, but at- needle-formed crystallisation, are sufficient to 
tract a little humidity if it be damp; are solu^ distinguish it from every thing else. The 
ble in one part of hot and two of cold water ; immediate rejection from the stomach of tiiis 
and are decomposable by a red heat, leaving add by an emetic, aided by copious draughts 
a small quantity of coaly residuum. 100 of warm water containing bicarbonate of 
parts of alcohol take up nearly 56 at a bdU potash, or sods, chalk, or carbonate of mi^ 
ii^ heat, but not above 40 cold, llidr aci- nesia, are the proper remedies. 
dity is so great, that when dissolved in 3600 With baryta it forms an insoluble salt ; but 
times their weight of water, the solution red- this salt will dissolve in water sddulated with 
dens litmus paper, and is perceptibly acid to oxalic add, and afford angular crystals. If, 
lbs taste. however, we attempt to dissolve these crystals 

Ibe oxalic acid is a good test finr detecting in boiling water, the excess of add will unite 

fime, which it separates from all the other with the water, and leave the oxalate^ which 

add^ unless they are present in excess. It will be predpitated. 

has likewise a greater affinity for lime than The oxalate of strontia, too^ is a nesriy 

tar any other of the bases, and ibrms with it soluble compound. 

a pulverulent insoluble salt^ not readily de- Oxalate of magnesia, too^ is Insoluble, un> 

compceable except by fire, and turning syrup less the acid be in excess, 

of violets green. Hie oxalate of potash exists in two states* 

From the oxalate of lead, Berselius infers that of a neutral salt, and that of an addule. 
its prime equivalent to be 4k55S, and by igne- The latter is generally obtained from the juice 
ODs decomposition he finds it resolved into of the leaves of the oraiis aceiouUat vvood 
66^53^ oxygen, 33.222 carbon, and 0.244 sorrel, or rtimeracetoM, common sorreL The 
hydrogen. Snce Berzelius published his ana- expressed juice, bang diluted with water, 
lysis, oxalic add has been made the subject should be set by for a few days, till the fecu- 
of some ingenious remarks by Doberdner, in lent parts have subdded, and the supema- 
the IGth voL of Schweigger's JoumaL We tant fluid is become clear ; or it may be cla- 
see that the carbon and oxygen are to each rified, when expressed, with the whites' of 
other in the simple ratio of one to two ; or re- ^ggs. It is then to be stndned off, e^po- 
fened to their prime equivalent^ as two of car- rated to a pellide^ and set in a cool place to 
bon ^ 1,5, to three of oxygen ^3.0. Hiis crystallize. The first product of crystals he- 
proportion is what would result from a prime ing taken out, the liquor may be further eva- 
of carbonic add ^ C -f- 2. O, combined porated and crystallised, and the same pro- 
with one of carbonic oxide^ s= C -f- Q. C cess repeated till no more can be obtained. 
fr^ng carbon, and O oxygen. The sum of In this way, Schlereth informs us, about nine 
the above wdghts gives ^5 for the prime drachms of crystals may be obtained from 
equivalent of oxalic add, disregarding by- two pounds of juice, which are generally a£» 
dragen, which constitutes but l-37th of the forded by ten pounds of wood sorreL Sa- 
whde^ and may be referred to Uie imperfect vary however says, that ten parts of wood 
desiccation of the oxalate of lead subjected to sorrel in full vegetation yield five parts of 
analysis. juice, which give littie more than a two-hun- 

I have found in my experiments (FhiL dredth of tolerably pore salt He boiled 
TnoB. 1822), that dry oxalate of lead ignited down the juice, however, in the first instance^ 
in rtmtHf* widi calomel in a glass tube^ yidds without clarifying it ; and was obliged re- 
no trace of muriatic add ; a certdn proof that peatedly to dissolve and recrystallize the salt 
no hydrogen exists in dry oxalic add. I to obtain it white. ■ 

found the prime equivalent of oxalic add, in This salt is in small, white, needly, or la- 

aystals, to be 1S75, containing three atoms mdlar crystals, not alterable in the air. It 

of water associated with the two atoms of car- unites with baryta, magnesia, soda, ammonia, 

bonand three of oxygen, which alone enter and most of the metallic oxides, into triple 

into the -above combination with oxide of salts. Yet its solution predpitates the nitric 

lead, and which wdgh 4v5. solutions of mercury and silver in the state 



ACID 84 PHOSPHATIC. 

of iosoliible oxi^tes of these meCals, the ni- nsped, pressed, and waihed with common 

trie acid in this case combining with the water, tiU the latter passed off limpid. Every 

potash. It attacks iron, lead, tin, sine, and 100 parts of the pressed carrot, with 5 parts 

antimony. of bicarbonate of potash, were boiled in water 

This salt, besides its use in taking out ink the usual time^ to form a clear fluid, and then 
spots, and as a test of lime, forms with sugar pressed ; a strong solution of pectate of pot- 
and water a pleasant cooling beverage ; and, ash was thua formed, which, being decompos- 
according to BerthoUet, it possesses consider- ed by excess of muriate of lime, gave an in- 
able powers as an antiseptic soluble pectate of lime. This was washed 

The neutral oxalate of potash is very so- and treated with water acidulated with mu- 

luble^ and assumes a gelatinous form, but riatic acid, and Anally with pure water. The 

may be brought to crystallize in hexs^dral pectic acid thus obtained was very pure, and 

prisms with diedral summits, by adding more far whiter than that obtained by the use of 

potash to the liquor than is sufficient to satu- the caustic alkali, 

rate the acid. See Salts (Table of). Carbonate of soda, cautiously employed. 

Oxalate of soda likewise exists in two dif- nuiy prove an economic substitute for the 

ferent states, those of an acidulous and a neu- bicarbonate of potash, 

tral salt, which, in their properties, are an*- If an excess of caustic potash be added to 

logons to those of potash. gelatinous pectic add in a platina crucible^ 

If oxalic acid be saturated with ammonia, and gradually heated and agitated, the mix- 

we obtain a neutral oxalate, which, on eva- ture soon liquefies and becomes brown. So 

poration, yields very fine crystals in tetrae- soon as by gradual evaporation the whole of 

dral prisms with diedral summits, one of the the water is dissipated, the saline matter, by 

planes of which cuts off* three sides of the careful management of the heat, becomes ra- 

prism. This salt is decomposable by fire, pidly white. 

which raises from it carl>onate of ammonia, By examination it is then found, dmt the 

and leaves only some slight traces of a coaly alkali is nearly neutralized, and that, when 

residuum. Lime, baryta and strontia, unite dissolved, nitric acid evolves a little carbonic 

with its add, and the ammonia flies off in add, but no pectic add ; and by further ex- 

the form of gas. Its constituents are, add amination the potash will be found neutra- 

4.6, ammonia 2.125> water 2.25, s=s 8.875. lized almost entirely by oxalic acidt formed 

The oxalic acid readily dissolves alumina, at the expense of the pectic add first added, 

and the solution gives on evaporation a yellow- •'^Ann. de Chim» xli. 4^ 

ish transparent mass, sweet, and a little astrin- A CI D ( PH OCENI C). The odorous 

gent to the taste, deliquescent, and reddening prindple of the soap of the dolphin oils, ac- 

tincture of litmus, but not syrup of violets, cording to M. Chevrenl. The sp. gr. of 

This salt swdls up in the fire, loses its add, phocenic add is 0.932. It is colourless, and 

and leaves the alumina a little coloured. takes 100 parts of water to dissolve 5.5 of it. 

The composition of the different oxalates It is soluble in alcohol in every proportion, 

may be ascertained by conudering the neutral Its constituents are in volume, 3 of oxygen, 

salts as consisting of one prime.of add ^ 4.5 10 of carbon, and 14 of hydrogen. 100 of 

to one of base, and the binoxylate of potash phocenic add neutralize 82.77 of baryta, 

of 2 of add to one of base, as was first proved forming a salt soluble in its own wdght of 

by Dr WoUaston. But this eminent philo- water at 68° F. The disagreeable smell of 

sopher has further shown, that oxalic add is leather dressed with fish oil, is ascribed by 

capable of combining in four proportions with M. Chevreul to the decomposition of the 

the oxides, whence result neutral oxalates, phocenic add contained in this oil.—- ^nn. de 

suboxalates, addulous oxalates, andaddoxa- Cfiim, et de Phy$, xxiii. 16. 

lates. The neutral contain twice as much ACID (PHOSPHATIC). This add is 

add as the suboxalates ; one-half of the quan> obtained by the slow combustion of cylinders 

tity of add in the addulous oxalates ; and of phosphorus in the air. For which purpose 

one-quarter of that in the add oxalates. See it is necessary that the air be renewed to sup- 

Salt. port the combustion ; that it be humid, other- 

ACID (PECTIC). The name given by wise the dry coat of pfaosphatie add would 

Braconnot to an add which he conceives to screen the phosphorus from farther action of 

be universally diffused through vegetables, the oxygen ; and that the different cylinders 

imd analogous to, if not identical with jelly, of phosphorus be insulated, to prevent the 

85 of this add seem to neutralize 15 of pot- heat from becoming too high, which would 

ash, and afford a compound like gum-arabic melt or inflame them, so as to produce phos- 

•— if fin. de Chim. et de Phys. xxviiL 173. phoric acid. The add, as it is formed, must be 

Vauquelin has recently described processes collected in a vessel, so as to lose as little of it 

by which this substance may be obtained as possible. All these conditions may be thus 

pure, and has pointed out several new pro- fulfilled :— -We take a pared of glass tubes, 

perties. which are drawn out to a point at one end ; 

A yellow variety of Zanders carrot was we introduce into each a cylinder of phos- 



ACID 85 PHOSPHORIC. 



pbomt a Itttk ihottor than the tube; we die- pens by evapoimtion. A large quantity of 

peee of theee tubes alongdde of one another, water must then be added, the whole strained - 

to tbe anooant of 90 or 40, in a glass funnel, thnmgfa a sieve, and the residual matter, 

the beak of which passes into a bottle placed which is sulphate of lime, must l>e edulco- 

on a plate covered with water. We then rated by repeated affUsions of hot water, till 

cover the bottle and its funnel with a large it passes tasteless. The waters contain pboa- 

beU-glass, having a small hole in its top^ and phoric acid with a little lime ; and by evapo- 

anotber in its side. ration, first in glazed earthen, and then in 

A film of phosphorus first evaporates, then glass, vessels, (or rather in vessels of platina or 

qombinew with the oxygen and the water of silver, for the hot add acts upon glass), afford 

the air, giving birth to pho8|rfiatic acid, which the impure acid in a concentrated state, which, 

ooUecta in sooali drops at tbe end of the glass by the force of a strong heat in a crucible, 

tubes, and fidls through the funnel into the may be made to acquire the fbrm of a trana- 

bottle^ A little phogphaticacid is also fbund parent consistent glass, though, indeed, it is 

oo the aides of the beLUglass, and in the wa- usually of a milky opaque appearance. 
ter of the plate. Hie process is a very slow For making phosphorus, it is not necessary 

one. to evaporate Uie water further than to bring 

The phoaphatic acid thus ooUe c ted is very it to the consistence of syrup. But when the 

dQuie. We reduce it to a viadd consistence, add is required in a pure state, it is proper 

by heating it gently ; and better still, by to add a quantity of carbonate of ammonia, 

putting it, at the ordinaiy temperature^ into a which, by double elective attraction, predpi- 

capaole over another capsule full of conoen- tates the lime that was held in solution by the 

tnited sulphuric add, under the recover of phosphoric add. Hie fluid being then eva- 

an air-pump, from which we exhaust the air. porated, afibrdsaorystallixed ammoniacal salt, 

The add thus formed is a visdd liquid, which may be melted in a sUver vessel, as the 
vrttbout colour, having a faint smell of pbos- add acts upon glass or earthen vessels. The 
pboms^ a strong taste^ reddening strongly the ammonia is driven off by the heat, and the 
tincture of litmus, and denser than water in add acquires the form of a compact glass, aa 
a proportion not well determined. Every transparent as rock-crystal, acid to the taste^ 
thing leads to the belief that this add would soluble in water, and deliquescent in the air. 
be solid, oould we deprive it of water. When This add is commonly pure, but neverthe- 
it is heated in a retort, phospburetted hydrogen less may contain a small quantity of soda, 
gas is evolved, and phosphoric acid remains, originally existing in the bones, and not ca- 
Hie oxygen and hydrogen of the water concur pable of bdng taken away by this process, in- 
to tfab transformation. Fhosphatic add has genious as it is. The only unequivocal mo- 
no action, either on oxygen gas, or on the at- thod of obtaining a pure add appeiira to con- 
moepheric air at ordinary temperatures. In sist in first converting it into phosphorus by 
combining with water, a slight degree of heat distillation of the maffriah with duurcoal, and 

then converting this again into add by rapid 



From the experiments of M. Thenard, this combustion, at a high temperature, dther in 

add seems to consist (exclusive of water) oxygen or atmospheric air, or some other 

of 100 phosphorus united to about 110 oxy- equivalent process, 
gen. Phosphorus may also be converted tnto* 

M. Dulong has shown, that the phosphatic the acid state by treating it with nitric add. 

add, in its action on the salifiable bases, is In this operation, a tubulated retort with a 

transfbrmed into pbospbonis and phosphoric ground-stopper must be half-filled with nitric 

adds, whence proceed phosphites and pbos- add, and a gentle heat .applied. A small 

phatea. piece of phosphorus bdng then introduced* 

These proportions agree nearly with two through the tube, will be dissolved with ef- 
primeaof phosphorus^ (2 X'^)^dX 9 of fervescence, produced by the escape of a 
oxygen ss 9. large quantity of nitric oxideu The addition 
ACID(PHOSPHORIC). Bonesofbee^ of phosphorus must be continued until the 
mnttoo, or veal, bdng caldned to whiteness in last piece remains undisscdved. The fire be- 
an open fire^ lose almost half of their weight, ing then raised to drive over the remainder of 
Tlwae must be poundbd, and sifted ; or tbe the nitric add, tbe phosphoric add will be 
trDablemaybespared,by buying the powder found in the retort, partly in the concrete 
that is sold to make cupels for the aasayers, and partly in the liquid form. 
and is, in fiict, the powder of burned bones When phosphorus is burned by a strong 
ready aifted. To three pounds of the powder heat, suffident to cause it to fiame rapidly, it 
there may be added about two pounds of con- is almost perfectly converted into dry add, 
centnted sulphuric add. Four or five pounds some of which is thrown up by the force of 
of water must be also added to assist the action the combustion, and the rest remains upon 
of the add. Tbe whole may be then left on the supporter. 

a gentle sand heat for two or three days, tak^ This substance has also been addified by 

ing care to supply tbe km of water which hap- the direct application of oxygen gas passed 



ACID 86 HYPOFHOSPHOROUS. 

through hot wataf, in which the phoBphoroB other at ad elefated tenpmttiin, a Kcptid' 

was liquefied or fused. called pfrolochloride of phoaphorua is formed. 

Ibe general characters of phosphoric .acid Water added to this, resolves it into muiiatic 
are»— -1. It is soluble in water in all propor- and phosphorous acids. A noderste heat 
tions, producing a specific ^Tity which in- suffices to expel the former, and the latter re- 
creases as the quantity of acid is greater, but mains associated with water. It has a Teiy 
does not exceed 2.687, which is that of the sour taste, reddens vegeCsble blues, and neu- 
gladal add. 2, It produces heat when mixed tralixes bases. When heated strongly in open 
with water, though not very considerable. S. vessels, it inflames. Phoephurettad hydrogen 
It has no smell when pure^ and its taste is flics off, and phosphoric add remains. Tan 
sour, but not ooirosiveb 4b When perfectly parts of it heated in close vessels, give off one- 
dry, it sublimes in close vessels ; but loses this half of a phosphuretted hydrogen, and leave 
property by the addition of water ; in which 8( of phosphoric add. Hence the liquid 
drcnmstonce it greatly differs from the boradc add consisto of 80.7 add -)- 19.3 vrater. See 
acid, which is fixed when dry, but rises by FBOs. Hydboobn. 

the help of water. 5. When considerably di- ACID(HYPOPHOSPHOROUS),hte. 

luted with water, and evaporated, the aqueous ]y discovered by M. Dulong. Pour water 

vapour carries up a small portion of the add. on the phosphuret of baryta, and wait till all 

6. With charcoal or inflammable matter, in a the phosphuretted hydrogen be disengaged, 

strong heat, it loses its oxygen, and becomes Add cautiously to the filtered liquid dilute 

converted into phosphorus. sulphuric add, till the baryta be all predpi- 

Fhosphoric acid is difiicult of crystallizing, tated in the state of sulphirte. The superne^ 

Though phosphoric acid is scarcely oorro- tant liquid is hypophosphorous acid, which 

sive» yet, when concentrated, it acts upon oils, should be passed through a filter. This li- 

which it discoloun and at length blackens, quid may be concentrated by evaporation, till 

producing heat, and a strong smell like that it becomes visdd. It has a very sour taste^ 

of ether and oil of turpentine ; but does not ' reddens vegetable blues, and does not crys- 

form a true add soap. It has most effect on tallize. Dulong assigns 100 phosphorus t<^ 

essential oils, less on drying oils, and least 37.44 oxygen, which gives the proportion of 

of all on £Eit oils. 1 atom phosphorus 4.0-^ If oxygen 1.6 es 

Ordinary phoaphoric add forms with oxide &6 for the add prime equivalent. The hy- 

of silver a yellow phoaphate, but if the add is pophosphites have the remarkable property of 

previously subjected to ignition; the silver being all soluble in water; while many of 

compound is whitei Mr Clark had previoua- the phosphates and phosphites are insduble. 

ly shown, that common phosphate of soda, According to M. Rose, the hypophosphitea 

which predpitates nitrate of silver yellow, is of lime, baryta, and ttrontia, may be prepar- 

changed by heat into what he calls a pyro- ed by boiling the earths with phosphorus and 

phosphate^ which predpitates nitrate of silver vrater. In preparing that of lime, the pboa^ 

white. phorus should not be added before the milk 

The experiments of Benelius show it to of lime boils ; and the operation should be 
be a compound of about 100 phosphorus -}" continued till all the phosphorus has disap- 
128 oxygen. M. Dulong,* in an elaborate peered, and the peculiar smell has ceased, 
paper published in the third volume of the Carbonic add is then to be passed through 
Memoires D* Arcueil, gives, as the result of to separate the excess of caustic lime, the in- 
diversified experiments, nearly the proportions soluble parts separated by the filter, and the 
of 100 phosphorus to 123 oxygen; or of 5 solution evaporated under the air-pump, or 
oxygen -f- 4 phosphorus =s 9, for the add in close vessels by beat. It then cryatalliaea 
equivalent with more or less water, according to drcum- 

M. Dumas, in an elaborate memoir on Phoa- stances, those obtained by heat having the 

phuretted Hydrogen (Annales de Chim, et de least 

jPftyi. xxxi.}, endeavoun to show that phos- The hypophosphites of baryta and strontie 

phone add consists of 1 atom of phosphorus may be prepared in the same way, and have 

4.0 -|- 5 atoms of oxygen 5 =s 9 ; while the same general properties. These earthy 

phosphorous add consists of 1 atom of phos- salts are insoluble in alcohol, 

phorus 4 -|- 3 atoms of oxygen 3 s= 7. See The alkattne hypophosphites may be made 

Fho8PHURI£TTBD Hyobogen, and General dther directly, or by mixing hypophosphite 

Table of Gases. of lime with excess of the alkaline carbcmate^ 

If phosphoric add be made 9, then in the filtering, evaporating to dryness, and digeat- 

phosphates of soda, baryta, and lead, we must ing in alcohol, by which the alkaline hypc^oa- 

admit 2 atoms of base ; thus giving them the phitcs are dissolved. The potash salt is the 

characters of subsalts, whicb that of soda ma^ most deliquescent salt known to M. Rose ; 

niftstly possesses. the soda salt is less so, crfBtallliing in ree- 

ACID (PHOSPHOROUS) was disco- tanguiar prisms, 

vered in 1812 by Sir H. Davy. When phos- AH the hypophosphites are soluble in wa^ 

phorus and corrosive sublimate act on each ter. The hypophosphonNis add was obtain- 



ACID 87 HYPOPHOSPHOROU& 

ed pure, and in qiunthj» by boiling tlw bf- alon« or combined with pbotpbate of soda. 

dnite of baryta with water and phoephanis The htmt haruhom of the shops is a pboft- * 

till all garlic odour ceased ; filtering the U- phate of lime. 

quid* and decomposing it by sulphuric add An acidulous phosphate of lune is found in 
in excess ; separating the precipitate^ and di- human urine, and may be crystallised in small 
geating the dear fluid ibr a short time with silky filaments, or shining scales, which unite 
an escess of oxide of lead j then filtering the together into something Uke the consutenoe of 
atilpbate of lead from the solution of hypo- honey, and have a perceptibly add taste. It 
phosphite^ and decomposing the latter by a may be prepared by partially decompodng the 
carrent of sulphuretted hydrpgen. The acid calcareous phosphate of bones by the sulphu- 
freed from the suiphuret of lead, may be oo»* ric, nitric, or muriatic add, or by dissolTing. 
centrated until strong enough to form the that phosphate in phosphoric add. It is so- 
required salts. luble in water, and crystallisable. Exposed 

With legaid to the phosphates and phoa* to the action of heat, it softens, liquefies, 

phites, we have many discrepandes in our swells up, becomes dry, and may be fused 

latest publications. Sir H. Davy says, in his into a transparent glass, which is insipid, in^ 

last memoir on some of the combinations of soluble, and unalterable in the air. In these 

phosphorus, that " new researches are requir- characters it differs from the glacial add of 

ed to explain the anomalies presented by the phoephorus. It is partly decomposable by 

phosphates.** charcoal, so as to afford phosphorus. 

Phosphoric add» united with baryta, pro- By pouring phosphate of soda into muriate 

daees an insoluble salt, in the form of a heavy of lime^ Beneliosobtaineda phosphateof linw, 

white powder, fusible at a high temperature consisting of add 100, lime 84w53l Hm 

into a grey enameL The best mode of pre* theoretic proportions are^ 
paring it is, by adding an alkaline phosphate Phosphoric add ss 9 as 100 

to the nitrate or muriate of baryta. Lime 3.5 X ^ss 7 sss 76 nearly. 

By mixing phosphate of ammonia with Phosphate of potash is very deliquescent, 

nitrate of bsryta, Benelius found that 68.2 and not crystallisable^ but condensing into a 

parta of baryta and 31.8 of phosphorus com- kind of jelly. Like the preceding spedes^ 

p os e d 100 of the phosphate. Hence it is a it first undergoes the aqueous fusion, swells^ 

eohphoqihate^ and consists of, dries, and may be fused into a glass; but this 

Pboaphoricadd latom^ 9.0 68^48 glass deliquesces. It has a sweetish saline 

Baryta 9 ^ 19.6 31.58 taste. Phosphate of soda is now commonly 

H I prepared by adding to the addulous phosphate 

100.0 of lime as much carbonate of soda in solution 

He made a phosphate by dissolving the above as will fully saturate the add. The carbonate 

in ^ute phosphoric add^ and evaporating, of lime which predpitates bang separated by 

when crystals were obtained composed, in 100 filtration, the liquid is duly evaporated so as 

parte, of add 48.64^ baryta 46.46, water 11. to crystallise the phosphate of soda; but if 

But by theory we have, there be not a slight excess of alkali, the cry»> 

Add, 2 atoms 18 42.857) tals will not be large and reguUff. Thecrya- 

Baae, 2 19.5 46.430 ( 100.000 tals are rhomboidal prisms of difi*erent shapes, 

Water, 4 4.5 10.713 > efflorescent, soluble in three parts of cokl and 

By pouring a solution of the preceding salt 1^ of hot water. Tbey are capable of being 

into alcohol, a sesquiphosphate is obtained, in fused into an opaque white glass, which may 

the form of a %ht white powder, containing be again dissolved and crysteUiaed. It may 

1^ times as much add as the subpbosphate. be converted into an adduloua phosphate by 

Hie phosphate of strontia differs from the an addition of add, or by dther of the strong 
preoediiig^ in bdng soluble in an excess of its adds, which partially, but not wholly, de- 
acid, compose it. As its taste is simply saline^ 

Fboephate of lime is very abundant in the without any thing disagreeable, it is much 

native state. See Apatite. It likewise con^ used as a purgative, chiefly in broth, in which 

atitutes the chief part of the bones of all am- it is not distinguishable from common salt 

malsb For this el^^ant addition to our pharmaoeo- 

Phosphate of lime is very difficult to fuse^ • tical preparatioos, we are indebted to Dr 

but in a glsashonse furnace it softens, and Pearson. In assays with the blowpipe it is 

acquires the semitransparency and grain of of great utility ; and it has been used instead 

porvdain. It is insoluble in water, but when of borax for soldering. 
weD caldned, forms a kind of paste with it^ as In crystals, this salt is c o mp osed, according 

in making cupels. Besides this use of it, it to Berselius, of phosphoric add 20.33, soda 

la employed Ibr polishing gems and metals, 17.67, water 62.00 ; and in the dry state, of 

for absorbinggreasefrom cloth, linen, or paper, add 53*48^ soda 46.52. If it be represented 

and Ibr preparing phosphorus. In medidne it by 1 atom of add =s 9 -|- 2 atoms soda ar 8, 

baa been strongly recommended against the then 100 of the dry salt will consist of add 53, 

rickets by Dr Bonhorame of Avignon, dther base 47 ; and, in the crystallised states o^— 



Water, 


diatoms 


87 


01.4 


Add, 


1 


9 


20.4 


Soda, 


2 


8 


las 



ACID 86 PURPURIC. 

the iolubflitjr of the phoaphate of ammoiiia, 
tbii triple salt is far las soluble than the phos- 
phate of magnfwa. It is partially deoompo- 

— ^» sable into phosphorus by charcoal, in conso- 

100.0 quenoe of its ammonia, 

which presents a good accordance witii the The phosphate of glucina has been ezamin- 

eiperimental results of Bercelius. ed by Vauqudin, who informs us, that it is a 

I must here notice the curious observations white powder, or mucilaginous mass, without 

of Mr Thomas Clark on this salt He iiods, any perceptible taste; fusible, but not decom- 

that when phosphate of soda is ignited, it ac- poaable by heat ; unalterable in the air, and 

quires peculiar p ropert i es, though its oompo- insoluble unless in an excess of its add. 

sition is unchanged. It then precipitates It has been observed, that the phosphoric 

nitrate of silver from its watery solution, not add, aided by heat, acts upon silex ; and we 

yeUow, but white ; and fumiriies a supema- may add, that it entera into many artificial 

tant liquid, not addulous, as with the com- gems in the state of a siliceous phosphate, 

mon phosphate, but neutraL To this modi- See Salt. 

fication of the salt he gives the name of ;;>yro- ACID (PINIC). In the colophony of 

phosphate of soda. He considers the phos- F^nnce (rosin), derived in all probability from 

phate of soda to contain, in its crystallized the pitau maritima or pmatieTf M. Baup has 

state, 25 atoms of water ; of whidi 24 are found a substance which crystallises in trian? 

separable by a sand bath heat^ and the 25th gular plates, soluble in about four parts of 

by a red heat. In losing this one proportion aloohoJ, but insoluble in water. It reacts like 

of water, phosphate of soda becomes pyro- an add, and neutralises alkaline matter. He 

phosphate. He finds arseniate of soda to calls it Pinic acid.— ^unaiies de Chinu et de 

resemble it in containing 25 prime propor- Phys* xxzL 

tions- of water, the last one of which is sep»- Pinic add has been found, by M. Unver- 

rsble only at a red beat. Hiis is in accord- dort>en, to be a constituent of Venice turpeiw 

anoe with M. Mitscherlich's views of the tine. 

isomorphism and analogous constitution of When Venice turpentine has been distilled 

the arseniates and phosplmtes. The arseniates with 20 parts of water, till half the water has 



of soda, howev<7, acquire no new property passed over, and this operation has been 

by ignition. peated severs! times, a semi-visdd mixture of 

The phosphate of ammonia crystalUses in resin with oils is left in the retort. Hiis dis- 
prisms with four regular sides, terminating solved in alcohol of 65 per cent, gives a green 
in pyramids, and sometimes in bundles of predpitate, with an alcoholic solution of aoe- 
small needles. Its taste is cool, saline, pun- tate of copper. This predpitate is pinate of 
gent, and urinous. On the fire it comports copper, which being washed on a filter with 
itself like the preceding spedes, except that alcohol, and then delved in alcohol with a 
the whole of its base may be driven off by a little muriatic add, may have the pinic add 
continuance of the heat, leaving only the add predpitated by water, as a white, resinous, 
behind. It is but little more soluble in hot and transparent substance. Being then 
water than in cold, which takes up a fourth washed with boiHng water, the alcohol is ro- 
of its weight. It is pretty abundant in hn- moved, and it becomes a solid, inodorous, 
man urine. It is an excellent flux both for and almost insipid body. 
assays and the blowpipe, and in the firf>rica- The pinates of potash and soda are obtain- 
tion of coloured ghus and artifidal gems. ed by slowly boiling an ethereal solution of 

Phosphate of magnesia crystallizes in irre- pinic add, for a few minutes, with the alka- 
gular hexaiidral prisms, obliquely truncated ; line carbonates, filtering and evaporating the 
but is commonly pulverulent, as it effloresces solutions; the residuum is the alkaline pinate^ 
very quickly. It requires fifty parts of water a resinous, colourless mass, which dissolves 
to dissolve it Its taste is cool and sweetish, completely in boiling water. The pinate of 
TUs salt too is found in urine. Fourcroy and potash is predpiut«i from its concentrated 
Vauquelin have discovered it likewise in small solution, not only by an excess of potash or 
quantity in the bones of various animals, soda, but also by neutral salts, as sulphate of 
though not in those of man. Hie best wayof soda, muriate of soda, acetate of potash, &c. 
preparing it is by mixing equal parts of the The pinates of baryta, alumina, man- 
solutions of phosphate of soda and sulphate of ganese, and zinc, are insoluble in alcohd, 
magnesia, and leaving them some time at rest, very soluble in ether, and resemble earthy 
wh«:i the phosphate of magnesia will crystal- bodies, 
lize, and leave the sulphate of soda dissolved. According to M. Unveidoriien, the pinic 

Anammonia^magnesianphosphatehasbeen add should be placed immediately after the 

discovered in an intestinal calculus of a horse benzoic. 

by Fourcroy, and since by Bartholdi, and like- ACID (PURPURIC). The excrements 

wise by the fi»rmer in some human urinary of the serpent Boa ConUrictor consist of pure 

calculi. See Caixjulus. Notwithstandrog lithic add. Dr Prout found, that on digest- 



ACID 



80 



PYROCITRIC 



ing tiiU snbstuioe thus obtaiiied, or IWxm uri- 
nary calcoliy in dilute nitric acid, an e^^ 
feacencc takes place, and the lithic acid is 
^asolTed, fbnning a beautiful purple liquid. 
The excess of uitric acid being neutralized 
with ammonia, and the whole concentrated 
bj slow evaporation, the colour of the solu- 
tion becomes of a deeper purple ; and dark 
icd granular crystals, sometimes of a green- 
idi hue externally, soon begin to separate in 
abundance. Hiese crystals are a compound 
of f"W"«nM^ with the add principle in ques- 
tion. The ammonia was displaced by digest- 
ing the salt in a solution of caustic potash, 
tili the red colour entirely disappeared. This 
alkaline solution was then gradually dropped 
into dilute sulphuric acid, which, uniting with 
the poixsh, left the acid principle in a state of 

purity. 

Tlus acid principle is likewise produced 
from lithic add by chlorine, and also, but 
with more difficulty, by iodine. Dr Front, 
the discoverer of this new add, has, at the 
suggestion of Dr Wollaston, called it pur- 
puric add, because its saline compounds have 
for the most part a red or purple colour. 

Hiis acid, as obtained by the preceding 
process, usually exists in the form of -a very 
fine powder, of a sUghUy yellowish or cream 
colour ; and when examined with a magnifier, 
especially under water, appears to possess a 
pearly lustre. It has no smell, nor taste. Its 
wp. giaT. is considerably above water. It is 
acaicdy soluble in water.* One-tenth of a 
giain, boiled for a considerable time in 1000 
grains of water, was not entirely dissolved. 
The water, however, assumed a purple tint, 
probably, Dr Fkout thinks, from the forma- 
tion of a litlle purpurate of ammonia. Pur- 
puric arid is insoluble in alcohol and ether. 
Tbe mineral adds dissolve it only when they 
are concentrated. It does not affect litmus 
paper. By igniting it in contact with oxide 
of copper, be determined its composition to be, 
2 atoms hydrogen, 0.250 - 4.54 
2 carbon, 1.500 - 27.27 

2 oxygen, 2.000 - 36.36 

1 asote, 1.750 - 31.81 

5.50 99.98 

Purpuric add combines with the alkalis, al- 
kaline earths, and metallic oxides. It is ca- 
pable of expelling carbonic add from the 
alkaline carbonates by the assistance of hoit, 
and does not combine with any other add. 
Hiese are circumstances suffident, as Dr 
WoUaston observed, to distinguish it from 
an oxide, and to establish its character as an 



PuTfmraie of ammonia crystallizes in qua- 
dnngular prisms, of a deep garnet-red colour. 
It b soluble in 1500 parts of water at 60<>, and 
in much leas at the boiling temperature. The 
solution is of a beautiful deep carmine, or rose- 
red colour. It has a slightly sweetish taste, 



but no imdL Purpurate of potash is much 
more soluble ; that of soda is less; that of 
lime is nearly insoluble; those of strontia 
and lime are slightly soluble. All the solu- 
tions have the characteristic colour. Pur-^ 
purate of magnesia is Tery soluble ; and in 
solution, of a very beautiful colour. A so- 
lution of acetate of zinc produces, with pur- 
purate of ammonia, a solution and predpitate 
of a beautiful gold-yellow colour ; and a most 
brilliant iridescent pellide, in which green and 
yellow predominate, forms on the sur&ce of 
the solution. Dr Front concdves tbe salts 
to be anhydrous, or void of water, and com- 
posed of two atoms of add and one of base. 
The purpuric add and its compounds pro- 
bably constitute the bases of many animal 
and vegetable colours. Hie well known pink 
sediment which generally appears in the urine 
of those labouring under febrile affections, 
appears to owe its colour chiefly to the pur- 
purate of ammonia, and perhaps occasionally 
to the purpurate of soda. 

The solution of lithic add in nitric add 
stains the skin of a permanent colour, which 
becomes of a deep purple on exposure to the 
sun. These apparently sound experimental 
deductions of Dr Front have been called in 
question by M. Vauquelin; but Dr IVout 
ascribes M. Vauquelin*s failure in attempt- 
ing to* procure purpuric acid, to his having 
operated on an impure lithic add. I think 
entire confidence may be put in Dr Front's 
experiments. He says that it is difficult to 
obtain purpuric add from the lithic add of 
urinary concretions.— FAt^ Trans, for 1818^ 
and AnnaU of PkiL vol. xiv. 

ACID (PYROCITRIC). When citric 
add is put to distil in a retort, it b^ns at 
first by melting ; the water of crystallization 
separates almost entirely from it by a continu- 
ance of the fusion ; then it assumes a yellow- 
ish tint, which gradually deepens. At the 
same time there is disengaged a white vapour, 
which goes over to be condensed in the ra- 
cdver. Towards the end of the caldnation 
a brownish vapour is seen to form, and there 
remains in the bottom of the retort a light 
yery brilliant charcoal. 

The product contdned in the recdver con- 
sists of two different liquids. One, of an 
amber-yellow colour, and an oily aspect, oc- 
cupies the lower part; another, colourless 
and liquid 4ike water, of a very dedded add 
taste, floats above. After separating them 
from one another, we percdve that fiie first 
has a very strong bituminous odour, and an 
add and acrid taste ; that it reddens power- 
fully the tincture of litmus, but that it may 
be deprived almost entirely of that acidity by 
agitation with water, in which it divides itself 
into globules, which soon fall to the bottom 
of the vessel, and are not long in uniting into 
one mass, in the manner of dls hearier than 
virater. 



ACID 90 PYROCITRIC 



In this stale it poss c s M s some of the pnv don Ibrm. Iliis salt has a sharp taste. It 

perties of these substances; it is soluble in dissolfes in 85 parts of water at SKP Fahr. 

alcohol, ether, and the caustic alkalis. How- It contains 30 per cent of water of aystaUi^ 

ever, it does not long continue thus ; it be- cation, and is composed, in its dry ttate, of 
comes add, and sometimes even it is obsenr- Fyrocitric add, 34 

ed to deposit, at the end of some days, white lime, 66 

crystals, which haTe a very strong addity : if The solution of the pyrodtric add satura- 

we then agitate it anew with water, it di»- ted with baryta water, lets fall, at the end of 

solves in a great measure, and abandons a some hours, a very white crystalline powder, 

yellow or brownish pitchy matter, of a very which is pyrodtrate of baryta. This salt ia 

obvious empyreumatic smell, and which has soluble in 150 parts of cold water, and in 50 

much analogy yriih the oil obtained in the of boiling water. Two grammes of this salt, 

distillation of other v^^etable matters. The decomposed by sulphuric add, furnished 1.7 

same effect takes place when we keep it under of sulphate of baryta, which gives fiir its ooa^ 

water ; it diminishes gradually in volume, the position, 

water acquires a sour taste, and a thick oil I^^rodtric add, 43.9 

remains at the bottom of the vessel Baryta, 56. 1 

Hiis liquid may be regarded as a oombina> Hie pyrodtrate of lead is easily obtained 

tion (of little permanence indeed) of the pe- by pouring pyrodtrate of potash into a solu« 

culiar add with the oil farmed in similar dr- tion of acetate of lead. The pyrodtrate of 

cumstances. lead presents itself under the form of a white 

As to the liquid and colourless portion gelatinous semitransparent mass, which be- 

which floated over this oil, it was ascertained comes dry in the air, shrinking like gelatinous 

to contain no dtric acid carrigd over, nor alumina, to which, in its physical characters^ 

acetic add ; first, because on saturating it it has much analogy. It contains 8 per cent 

with carbonate of lime, a soluble calcareous of water, and is formed of 
salt was obtained ; and, secondly, because this Pyrodtric add, 33.4 

salt, treated with sulphuric add, evcdved no Protoxide of lead, 66.6 

odour of acetic add. Knowing the composition of pyrodtrate of 

fVom this calcareous salt the lime was se- lead, it was employed, by ignition with oxide 

parated by oxalic add ; or the salt itself was of copper, to determine that of the add itself, 

decomposed with acetate of lead, and the pre- which is stated as bdng 
dpitate treated with sulphuretted hydrogen. Cari)on, 47.5 

By these two processes, this new add was Oxygen, ' 43^5 

separated in a state of purity. Hydrogen, 9.0 

Propertiet of the pyrodtric acid.— Tliis ....^ 
add is white, inodorous, of a strongly add 100.0 
taste. It is difficult to make it .crystellixe in The proportion of the elements of this add 
a regular manner, but it is usually presented is very different then from that which MM. 
in a white mass, formed by the interlacement Gray Lussac, Thenard, and Berzelius, have 
<if very fine small needles. Projected on a found for dtric add. " But what is remark- 
hot body it melts, is converted into white very able, says M. Lassaigne^ its capacity for satu- 
pungent vapours, and leaves some traces of ration is nearly the same as that of dtric add, 
carbon. When heated in a retort, it affords as we may see by casting our eyes on the 
an oily-looking add, and yellowish liquid, analyses of the pyrodtrates of lime^ baryta, 
and is partially decomposed. It is very solu- and lead, which we have given, and which we 
ble in water and in alcohol ; water at the have convinced ourselves of by frequent veri- 
temperature of 10^ C. (50° F.) dissolves one- fication. Nevertheless, in the combination of 
third of its weight The watery solution has this new add, the ratio of the oxygen of the 
a strongly add taste ; it does not predpitate oxide to the oxy{(en of the add is in a dif- 
lime or baryta water, nor the greater part of ferent proportion from that admitted for the 
metallic solutions, with the exception of ace- neutral dtrates : we observe^ that in the py- 
tate of leadandprotonitrateof mercury. With rocitrates the oxygen of the base is to that of 
the oxides it forms salts possessing properties the add as I to 3.07; whilst in the dtratea 
difierent from the dtrstes. it is as 1 to 4^916." 

The pyrodtrate of potash crystallises in The author seems here to have miscalcu- 

small neMiles, which are whiter and unalter- lated strangely. Taking his analysis of pyio- 

able in the air. It dissolves in about 4 parts dtrate of lime and of pyrodtric add, we have 
of water. Its solution gives no predpitate 34 add, which contain 14.6 of oxygen, 
with the nitrate of silver or of baryte ; whilst 66 lime, - 18.6 of oxygen ; 

that of the dtrate of baryta forms predpitates so" that the oxygen of the base is to that of 

with these salts. the add as I to 0.785^ instead of 1 to a07. 

The pyrodtrate of lime directly formed, ex- In fact, the pyrodtrate of lime result 

hibits a white crystalline mass, composed of makes the atom of add, r e fe rr e d to Dr Wol- 

neadles opposed to each other, in a ramifica- laston'i scale^ to be 18.3; that for pyrod- 



ACID 



91 



PYROLITilia 



of toyttt mricflt it 7&Ai Mid tfaal for 
li y wxiUi i t of Iflwiy 70L The only ntpposi- 
tka we cao form i% tint the Dumbert for 
the calcareous salt are mverted in the Jour^ 
nai de Fharmades and that they ought to be» 
Pyrocitric add* 66 

Lfane, 34 

In tilufl caw the atom comes out 69.0; a 
mkislilr aocordaDoe with the above. Were 
the equivalent of the add 66.25^ then it 
nigfat consist of 

CkrixNi, 4 atoms s=s 3a00 45.27 
Oxygen^ 3 - =30.00 45.27 
Hydiiigai,5 - ess 6w25 9.46 

66.25 100.00 
ACID (PTROLIGNOUS). In the 
dietiuiliiii distillation of any kind of wood, 
an add is obtained, which was formerly 
oallad aeki tpirit cfwody and since, pyrolig- 
nous add. Fourcroy and Vauqnelin show- 
ed dut this add was merely the acetic, con- 
taminated with empyreumatic oil and bitu- 
men. See Acsnc Acux 

Under acetic add will be found a full ao- 
eooBt of the production and purification of 
pynlignous add. M. Monge disoorercd, 
about Atc years ago^ that this add has the 
j w upeity of preventing the decomposition of 
adiBBal substances. But I have lately learn- 
ed, that Mr William Dinsdal^ of Field Cot- 
ti^e, Cokfaester, three years prior to the date 
of M. Sionge's discovery, did propose to the 
Lords Commissioners of the Admiralty, to 
apply n pyrolignons acid, (prepared out of 
the contact of iron vessels, which blacken it), 
to the purpose of preserving animal food, 
w l i e r ev er thdr ships mi^t go. As this 
■ppBcsirion may in many cases aiFoid valu- 
able aodscortRitic artides of food, and thence 
be eminently condudve to the health of 8e»- 
SMD, it is to be hoped that their Lordships 
wiU, ere long, carry into effect Mr Dinsdale's 
ingenious plan, as for as shall be deemed 
necessary. It is suffident to plunge meat 
for n fow moments into this add, even 
aligfatly emp y re u matic, to preserve it as long 
as you please. « Putrefocdon,*' it is said, 
•* not only stops, but retrogrades." To the 
e mpyr e u matic oil a part' of this eff^ has 
bem ascribed ; and hence has been accounted 
for, the agency of smoke in the preservation 
of tangoes, bams, herrings, &c. Dr Jorg of 
Lsipsic has entirely recov e red several ana- 
tandcal preparations from indpient corrup- 
tion by pouring this add over them. ' With 
the empy r eumatic oil or tsr he has smeared 
pieces of flesh already advanced in decay, 
and notwithstanding that the weather was 
hot, they soon beomie dry and sound. To 
the above statements Mr Ramsay of Glas- 
gow, an eminent manufacturer of pyrolig- 
nons add, and wdl known for the pnri^ 
of liis vinegar from wood, has recently added 
Hm foUoirii^ foots in the 5th nmnbeic €f the 



Edinbmgh PhilosophkalJoBnaL Iffishbe 
simply dqpped in redistilled pyroUgnous acid, 
of the spedfic gravity 1.012, and afterwards 
dried in the shade, they preserve perfectly 
welL On boiling herrings treated in this 
manner, they were very agreeable to the 
taste^ and had nothing of the disagreeable 
empyreuma which those of his earlier expe- 
riments had, which were steeped for three 
hours in the add. A number of very fine 
haddocks were cleaned, split, and slightly 
sprinkled with salt for six hours. After 
bring drained, they were dipped for about 
three seconds in pyrolignous add, then hung 
up in the shade for six days. On being 
broiled, the fish were of an uncommonly fine 
flavour, and delicately white. Beef treated 
in the lame way had the same flavour as 
Hamburgh (wef, and kept as well. Mr 
Ramsay has since found, that his perfecdy 
purified vinegar, specific gravity 1.034, bring 
^plied by a cloth or sponge to the surfooe 
of fiesh ineat, makes it keep sweet and sound 
for several days longer in summer than it 
otherwise would. Immersion for a minute 
in his purified common vinegar, spedfic gra- 
vity 1.009, protects beef and fish from all 
taint in summer, provided they be hung up 
and dried in the shade. When, by frequent 
use, the pyrolignous acid has become impure^ 
it may be clarified by beating up twenty 
gallons of it with a dozen of eggs in the 
usual manner, and heating the mixture in 
an iron boiler. Before boiling, the eggs 
coagulate, and bring the impurities to the 
sorfoce of the boiler, which are of course to 
be carefoUy skimmed off. The add must 
be immediately withdrawn from the boiler, 
as it acts on iron. 

ACID (PYROLITHIC). When uric 
add concretions are distilled in a retort, sil- 
very white plates sublime. These are pyro- 
litlmte of ammonia. When thdr solution is 
poured into that of subacetaie of lead, apy- 
rolitbate of lead foils, which, after proper 
washing, is to be shaken with water, and de- 
composed by sulphuretted hydrogen gas. 
The supernatant liquid is now a solution of 
pyrolithic add, which yields small adcular 
crystals by evaporation. By heat these melt, 
and sublime in white needles. They are 
soluble in four parts of cold water, and the 
solution reddens vegetable blues. Boiling 
alcohol dissolves the add, but on cooling it 
deposits it, in small white grains. Nitric 
add dissolves without changing it. Hence, 
pyrolithic is a different add from the lithic, 
which, by nitric add, is convertible into pur- 
purate of ammonia. The pyrolithate of lime 
crystallizes in stalactites, which have a bitter 
and slightly acrid taste. It consists of 91.4 
add -I- &6 Ihne. Pyrolithate of baryta is 
a neariy insoluble ponder. The salts of pot- 
ash, soda, and ammonia, are soluble^ and the 
former two crystaUiiable. At a red heat. 



ACID 



92 



FYROMUCIC. 



and by pawipg it OTer ignited oxide of cop- 
per, it is decompooed, into oxygen 44.32, 
carbon 2a29, azote 16.84s hydrogen 10. 

ACID (PYROMALIC). When malic 
or Borbic acid, for they are the same, is dis- 
tilled in a retort, an add sublimate, in white 
needles, appears in the neck of the retort, 
and an acid liquid distils into the receiver. 
This liquid, by eraporation, affords crystals, 
constituting a peculiar add, to whidi the 
above name has been given. 

They are permanent in the air, melt at 
118° Fahr., and on cooling form a pearl- 
coloured mass of diverging needles. When 
thrown on red-hot coals, they completely 
evaporate in an acrid, cough-exciting smoke. 
Exposed to a strong beat in a retort, they are 
partly sublimed in needles, and are partly de- 
composed, lliey are veiy soluble in strong 
alcohol, and in double their wdght of water, 
at the ordinary temperature. Tlie solution 
reddens vegetable blues, and yields white 
flocculent predpitates with acetate of lead 
and nitrate of mercury; but produces no 
piedpitate with lime water. By mixing it 
with baryta water, a white powder falls, 
' which is redissolved by dilution with water, 
after which, by gentle evaporation, the pyro* 
malate of baryta may be obtained in silvery 
plates. These consist of 100 add, and 
185.142 baryta, or in prime equivalents, of 
5.25 + 9.75. 

Pyromalate of potash may be obtained 
in feather-formed crystals, which deliquesce. 
FyromalateW lead fonns first a white floccu- 
lent predpitate, soon passing into a semi- 
transparent jelly, which, by dilution and fil- 
tration from the water, yields brilliant pearly- 
looking needles. The white crystals that 
sublime in the original distillation, are con- 
sidered by M. Lassaigne as a peculiar add. 
ACID (PYROMUCIC). This add, 
discovered in 1818 by M. Houton Labillar- 
diere, is one of the products of the distillation 
of mudc acid. When we wish to procure it, 
the operation must be performed in a glass 
retort furnished with a recdver. The add 
is formed in the brown liquid which is pro- 
duced along with it, and which contains 
water, acetic acid, and empyreumatic oil ; a 
very small quanti^ of the pyromudc add 
remaining attached to the vault of the retort, 
under the form of crystals. These crystals 
being coloured are added to the brown liquor, 
which is then diluted with three or four times 
its quantity of water, in order to throw down 
a certain portion of oil. The whole is next 
filtered, and evaporated to a suitable degree. 
A great deal of acetic add is volatilized, and 
then the new add crystallizes. On decant- 
ing the mother waters, and concentrating 
them farther, they yield crystals anew ; but 
as these are small and yellowish, it is neces* 
sary to make them undergo a second distilla- 
tion, to render them susceptible of bdng per- 



fectly purified by crystallisation. 150 parts- 
of mudc add furnish about 60 of brovm 
liquor, from vrhich we can obtain dght to ten 
of pure pyromudc add. 

Hiis add is whiter inodorous, of a strongly 
add taste, and a dedded action on litmus. 
Exposed to heat in a retort it melts at the 
temperature of 266° F., then volatilizes, and 
condenses into a liquid, which passes on cool- * 
ing into a crystalline mass, covered with very 
fine needles. It leaves very slight traces of 
residuum in the bottom of the retort. 

On burning coals, it instantly diffuses 
wliite pungent vapours. Air has no acti^m 
on it Water at 60° dissolves l-28th of its 
weight Boiling water dissolves it much 
more abundantly, and on cooling abandons 
a portion of it, in small elongated plates» ; 
which cross in every direction. 

Subacetate of lead is the only salt of whose . 
oxide it throws down a portion. 

It consbts in 100 parts of 

Carbon, 52.118 

Oxygen, 45.806 

Hydrogen; 2.111 

Hiis add unites readily to the salifiable 
bases, and forms. 

With polatht a .salt very soluble in water 
and alcohol, deliquescent, and which, evapo- 
rated to a pellicle, congeals into a granular 
mass; 

f^ith toda^ a salt less deliquescent and leas 
soluble in water and alcohol than the pre- 
ceding, but which crystallizes vrith difiicul- 

With bartfla, JtroiUio, and lime, salts 
soluble in water, and a little more so in hot 
than in cold, insoluble in alcohol, and easily 
obtained in crystals, which are permanent in 
the air; 

With ammoniot a salt soluble in water, 
which, by evaporation of the liquid, loses a 
portion of its base, becomes add, and then 
crystallizes with &cility ; 

With protoxide of lead, a neutral soluble 
salt, which possesses remarkable properties. 
Hiis salt is obtained by putting liquid pyro- 
mudc add in contact with moist carbonate 
of lead. When we evaporate the solution, 
the salt collects at the surface in transparent 
liquid globules, of a brownish colour and an 
dly aspect ; which, a little after they are re- 
moved,, assume the softness and toughness of 
pitch, and finally become solid, opaque, and 
whitish. This property belongs also to suc- 
dnate of lead. 

The alkaline pyromucates occasion scarcely 
any turbidity in the solutions of the metallic 
salts, if we except those of the peroxide of 
iron, of the peroxide of mercury, the subace- 
tate of lead, and the protonitrate of tin. The 
deposit formed in the salts of iron is a yellow 
similar to that of turbeth mineral. 

In all the . salts in the neutral state, the 
quantity of oxygen in the oxide is to. the 



ACID 



93 



SEBACIC. 



^iwntity in the add as one to tUrteen, which 
sumber therefore represents the equivalent 
weight of pyromucic add.— ^nn. de Chim- 
a de Pktfi. ix. 365. 

ACID (PYROTARTARIC). Into a 
coated glass retort introduce tartar, or rather 
tartaric add, till it is half full, and fit to it a 
tubulated recdrer. Apply heat, which is to 
be gradually raised to rtdnesa. Fyrotartaric 
addT of a brown colour, from impurity, is 
fimnd in the liquid products. We must filter 
these through paper previously wetted, to se- 
parate the oily matter. Saturate the liquid 
with carbonate of potash ; evaporate to dry- 
ness; redissolve, and filter through clean 
moistened paper. By repeating thb process 
of ev a poration, solution, and filtration, seve^ 
ral times, we succeed in separating all the 
oiL The dry salt is then to be treated in a 
^aas retort^ at a moderate heat, with dilute 
sulphuric add. There passes over into the 
TCcdTer, first of all a liquor containing evi- 
dently acetic add; but towards the end of 
the distillation, there is condensed, in the 
vault of the retort, a white and foliated sub- 
limate^ which is the pyrotartaric add, per- 
fectly pure. 

It has a very sour taste, and reddens 
powerfully the tincture of turnsole. Heated 
in an open vessel, the add rises in a white 
sm<Ae, without leaving the charcoaly resi- 
duum which is left in a retort It is very 
soluble in water, from which it is separated 
in crystals by spontaneous evaporation. The 
bases combine with it, forming pyrotartrates, 
of which those of potash, soda, ammonia, 
baryta, strontia, and lime, are very soluble. 
That of potssh is deliquescent, soluble in al- 
oobolf capable of crystallizing in plates, like 
the acetate of potash. This pyrotartnte pre- 
dpitates both acetate of lead and nitrate of 
mercury, whilst the add itself predpitates 
only the latter. Rose is the discoverer of 
this add, which was formerly confounded 
with the acetic 

ACID (RACENIC). An add found 
associated with the tartaric in tartar, by M. 
Kcestner. M. Gay Lussac observed that it 
took lime from the muriate of that base. It 
consists of 4 atoms iyf carbon, 5 of oxygen, 
and 8 of hydrogen. Its prime equivalent is 
S.307. It forms very remarkable salts ; that 
vrith potash and soda resembles Rochelle salt 
M. GtLj Lussac considers it to be isomor- 
phous with the tartaric add. 

ACID (RHEUMIC). A supposed new 
add extracted from the stems of rhubarb; 
but it is merely the oxalic. 

ACID (ROSASIC). There is deposited 
from tlie urine of persons labouring under 
intermittent and nervous fevers, a sediment 
of a rose colour, occasionally in reddish crys- 
tals. This was first discovered to be a pecu- 
liar add by M. IVoust, and afterwards ex- 
amined by M. Vauquelin. This add is loiid, 



of a lively cinnabar hue, without smell, with 
a faint taste, but reddening litmus very sen- 
sibly. On burning coal it is decomposed 
into a pungent vapour, which has not the 
odour of burning animal noatter. It is very 
soluble ia water, and it even softens in the 
air. It is soluble in alcohol. It forms solu- 
ble salu with potash, soda, ammonia, baryta, 
strontia, and lime. It gives a slight rose- 
coloured predpitate with acetate of lead. It 
also combines with lithic add, forming so in- 
timate a union, that the lithic add in pred- 
pitating from urine carries the other, though 
a deliquescent substance, down along with it 
It is obtained pure by acting on the sedi- 
ment of urine with alcohol. Stt AaD (PuA- 

PUBIC). 

ACID (SACLACTIC). See Acid (Mu- 
cic). 

ACID (SEBACIC). Subject to a con- 
siderable heat 7 or 8 pounds of hog's lard, in 
a stoneware retort capable of holding dou- 
ble the quantity, and connect its beak by an 
adopter with a cooled recdver. The con- 
densible products are chiefly fat, altered by 
the fire, mixed with a little acetic and sebadc 
adds. Tkeat this product with boiling water 
several times, agitating the liquor, allowing it 
to cool, and decanting each time. Pour at 
last into the watery liquid, solution of acetate 
of lead in excess. A white flocculent preci- 
pitate of sebate of lead will instantly fall, 
which must be collected on a filter, washed 
and dried. Put the sebate of lead into a 
phial, and pour upon it its own weight of 
sulphuric add, diluted with five or six times 
its wdgbt of water. Expose this phial to a 
heat of about S12^. The sulphuric acid 
combines vdth the oxide of lead, and sets the 
sebadc add at liberty. Filter the whole 
while hot As the liquid cools, the sebadc 
add crystallizes, which must be washed, to 
free it completely from the adhering sulphu- 
ric add. Let it be then dried at a gentle 
heat 

Tlie sebadc add is inodorous ; its taste is 
slight, but it perceptibly reddens litmus pa- 
per ; its specific gravity is above that of water, 
and its crystals are small white needles of 
little coherence. Exposed to heat, it melts 
like fat, is decomposed, and partially evapcv- 
rated. The air has no eflTect upon it It is 
much more soluble in hot than in cold water ; 
hence boiling water saturated with it assumes 
a nearly solid consistence on cooling. Alco- 
hol dinolves it abundantly at the ordinary 
temperature. 

With the alkalis it forms soluble neutral 
salts ; but if we pour into their concentrated 
solutions, sulphuric, nitric, or muriatic adds, 
the sebadc is immediately deposited in laige 
quantity. It affords predpitates with the 
acetates and nitrates of lead, mercury, and 
silver. 

Such is the account given by M. Tbenard 



ACID 



M 



SUBERIC 



of thi$ add, in the 3d voluine of bb TVut^ 
de Chimie, publiihed in 1815. BeRelia% 
in 1816, published an ehiborate dissertation, 
to prove that M. Thenard's new eebacic add 
was only the bensoic, contaminated by the 
fat, firom which, however, it may be freed, 
and brought to the state of common benzoic 
acid. M. Tlienard takes no notice of M. 
Benelius whatever, but concludes his ac- 
count by stating, that it has been known only 
for twdve or thirteen years, and that it must 
not be confounded n^th ibe acid formerly 
called sebadc, which possesses a strong dis- 
gusting odour, and was merely acetic or mu- 
riatic acid ; or fat which had been changed, 
in some way or other, according to the pro- 
cess used in the preparation. 

ACID (SELENIC). There seems to 
be two add compounds of selenium, a selo- 
nious and selenic acid: the former is des- 
cribed under selenium, the latter we shall 
describe here. Hiis new compound was dis- 
covered by MM. Mitscherlich and Nitzsch. 
It contains half as much more oxygen as the 
M one discovered by M. Benelius. 

Seleniate of lead is to be decomposed by 
sulphuretted hydrogen, and the sdenic add 
is disengaged. Its purity is ascertained by its 
entire volatility. If sulphuric add be pre- 
sent, it may be detected by boiling a portion 
with muriatic add, which produces selenious 
add, and then testing by muriate of baryta; 
—a predpitate indicates sulphuric add. 
From the decomposition of seUniiate of pot- 
ash by muriate of baryta, it appeared that 
the seleniate was composed of 

Potash, 42. 16 

Selenic add, 57.84 



100.00 
lie composition of the add was determined 
by boiling a certain weight of the seleniate 
of soda with muriatic add in excess, and de- 
composing the sdenious add f<nrmed by sul- 
phite of soda ; 4.88 of the salt gave 2.02 of 
selenium, from which and the above result 
it would appear, that the add is formed of 
Selenium, 61.4 

Oxygen, 38.6 

loao 

Selenic add is a colourless liquid, which 
may be heated to 536° vrithout sensible de- 
composition*; above that it changes, and at 
554° is rapidly resolved into oxygen and se- 
lenious add. Heated to 329°, its spedfic 
gravity is 2.524; at 512.6<» it is 2.6. Se- 
lenic acid has a powerful attraction for water, 
and evolves much heat when mixed with it. 
When boiled with muriatic add, it produces 
Beleniou»add and chlorine ; and the mixture^ 
like aqua regia, will dissolve platina. Selenic 
add dissolves zinc and iron, evolving hydro- 
gen ; it dissolves copper with disengagement 



of aelenioiM add, and of itself it dinolvva 
gold, but not platina. 

Sdenic acid is but little inferior, in affimty 
for bases, to sulphuric add. Seleniate of 
baryta is not completely decomposed by sul- 
phuric add. Its combinations bdng isamor- 
pbous with those of sulphuric acid, and poa- 
sessing the same ciystalline forms, and the 
same general cheminl properties, exhibit but 
very slight differences from the sulphates. 

To prepare the seleniate of lead, the 8»- 
leniure^ freed from carbonates by muriatic 
add, is to be fused with its wdght of nitrate 
of soda in a red-hot crucible. Water theo 
dissolves out seleniate, nitrate, and nitrite of 
soda. Hie solution quickly boiled, depodti 
anhydrous seleniate of soda. Or seleniate of 
soda may be fused with nitrate. The seleniate 
is decomposed by nitrate of lead ; whence r». 
suit insoluble ■oifl"i«tf of lead and nitrite-of 
soda. See Selenium. 

ACID (SILICATED FLUORIC).^ 
See Acid (Fluoaic). 

ACID (SILVIC). A substance analo- 
gous to pinic acid, found in the resins of the 
pinui tUvesUrit and fir tree. It is separated 
by acting on the resin several times with al- 
cohol, which takes up every thing but the 
siivic add. The latter crystallizes almost en- 
tirely upon cooling, is colourless, and requires 
a higher temperature than 212^ for its fu^ 
don. The ciystals appear as quadrangular 
prisms. This add dissolves in all propor- 
tions in volatile oils ; and the alcoholic solu- 
tion strongly reddens litmus. The sUvate of 
copper is soluble in absolute alcohol, and 
may in that way be separated from the pinate 
of Uie same base. 

ACID (SOLANIC). Sohinia, which la 
piindpally contained in the berries of the con^ 
mon nightshade {$olanum nigrum),'iA combin- 
ed with a particular add. This add may be 
separated by means of ammonia, which pre- 
cipitates the vegeto^Ukali. It has a crystal- 
line form, is soluble in water, and prodnoea 
oystallizable combinations with potash and 
soda ; the fint in adcular crystals, the second 
in quadrilateral prisms, with a sweet tasta 

ACID (STEARIC). This add is the 
saponified fat of mutton, beef, pork, &c See 
Fat, and the details of its si^Kmification. 

ACID (STIBIC). See Acm (Ann- 
iionic) 

ACID (STIBIOUS). See Acm (An- 

TIMONIOCJS). 

ACID (SUBERIC). M. Cfaevrenl ob- 
tained the suberic add by mere digestion of 
the nitric arid on grated cork, without distil- 
lation, and purified it by veuhing with cold 
water. 12 parts of cork may Im made to 
yield 1 of add. When pure, it is white and 
pulverulent, having a feeble taste^ and little 
action on litmus. It is soluble in 80 parte 
of water at 55}° F. and in 38 parte at 140°. 



ACID 96 SULPHURIC 

It is mucfa more toluble in aloobol, IWmi duce ft peculiar doas of aalti, hes been dis- 

wfaidi water throws down a portion of the tinguished as the sulphonaphtbalic add.— 

suberic add. It occasions a white predpitate Let two parts of naphthaline and one part of 

when poured into acetate of lead, nitrates of concentrated sulphuric add be introduced 

lend, mercury and silver, muriate of tin, and into a flask, raise the temperature till the 

protosulphate of iron. It aiFords no predpi- naphthaline melts, and agitate. Combina- 

tate with solutions of copper or sine llie tion is effected, and, after cooling, two sub- 

sobemtes of potash, soda, and ammonia, are stances are found, both in the solid state. 

veiry soluble. The two latter may be readily The lighter is naphthaline, containing a little 

crystallised. Those of baryta, lime, magne- of the peculiar add. The lower and heavier 

ua, and alumina, are of sparing solubility. is also crystalline, but softer than the upper. 

ACID (SUCCINIC). It has long been It is red, of an add bitter taste, absorbs 

known that amber, when exposed to distills- moisture from the air, and consists prindpal- 

tioo» affords a crystallised substance, which ly of the hydrated peculiar add, contaim'ng 

subfimes into the upper part of the vessel. some unoombined n^hthaline. It is distin- 

M. Julin of Abo states, that by miiing with guished as the impure MoUd add. On rub- 

eoanely powdered amber I-lSffa part of sul- bing this with native carbonate of barytm in 

phuiic add, diluted with an equal wdght of a mortar, a soluble barytic salt was obtained, 

water, the succinic add will be produced in To the solution of this salt, sulphuric add 

about twice the quantity got in the old way. was carefully added just in quantity su£Bdent 

Several processes have been proposed for to predpitate the baryta; and after filtration 

purilying this add : that of Bichter appears a pure aqueous solution of the new add was 

to be the best. The add being disserved in obtained. Hiis solution is bitter, add, 

hot water, and filtered, is to be saturated with powerfully reddening vegetable blues, neu* 

potash or soda, and boiled with charcoal, tralizing bases, but not predpitating baryta 

which absorbs the oily matter. Hie solution or lead from their salts. When carefully 

bong filtered, nitrate of lead is added ; whence ev^iorated in vacuo, it affords a white, loli^ 

results an insoluble succinate of lead, from crystalline add, deliquescing in the air. It 

which, by digestion in the equivalent quantity melts at 212^ Fahr. and cryi^kallixes on cool- 

of sulphuric add, pure succinic add is sepi^ ing. Its salts are soluble in water and al- 

rated. mtrate or muriate of baryta will show coboL That of baryta is composed of an ' 

whether any sulphuric add remains mixed atom of baryta, 2 of sulphuric add, 20 of 

with the sucdnic solution ; and if so, it may charcoal, and 8 of hydrogen. Its saturating 

be withdrawn by digesting the liquid with a power is equal to one-half that of its suU 

little more sucdnate of leaid. Pure sucdnic phuric add. 

add may be obtained by evaporation, in white ACID (SULPHOVINIC). The name 

transparoit prismatic crystals. Tbdr taste is given by Vogel to an add, or class of adds, 

somewhat tharp, and they redden powerfully which may be obtained by digesting alcohol and 

tincture of turnsole. Heat melts and partially sulphuric add together with heat Salts call- 

decomposes succinic add. Air has no effect ed sulphovinatcs were first noticed about the 

upon it. It is soluble in both water and year 1800 by M. Debit, and afterwards treat- 

akohol, and much more so when they are ed of by M. Vogel ; but their nature was 

heated. Its prime equivalent, by Berselius, is never sscertained till Mr Hennel made his 

6.26 ; snd it is composed of 4b 51 bydrogen, investigations latdy on the sutrject. The 

47.6 carbon, 47.888 oxygen, in 100^ or 2 -^ sulphovinates are readily prepared by mixing 

4-^3 primes. equal wdghts of sulphuric add and alcohol. 

With baryta and lime the sucdnic add allowing the mixture to remain for half an 
ibnns salts but little soluble; and with mag^ hour, then adding carbonate of lead equal in 
neaia it unites into a thick gummy substance, weight to that of sulphuric acid first used, 
Ibe sucdnates of potash and ammonia are and filtering ; little else than sulphovinic add 
crystallizable and detiquescent ; that of soda is left in solution. This combined with bases 
does not attract moisture. The sucdnate of furnishes salts, which may be rendered pure 
ammonia is useful in analysis to separate by crystallization. Sulphovinic add, accord- 
oxide of iron. ing to Mr Hennel, consists of two atoms of 

ACID (SULPHOCYANIC). See m sulphuric acid, four of hydrogen, and four of 

the sequel of Acid (Htdbocyanic). carbon; and this compound add combines 

ACID (SULPHON APHTH ALIC) with one atom of potash to form sulphorinate 

Jfr Faraday communicated a paper, in 1826, of potash. The vegetable part of the add 

to the Royal Sodety, to show that during the is therefore olefiant gas. Oil of wine and 

mutual action of sulphuric add and naphtha- sulphovinic add seem to be identical.-— PAtf. 

fine^ a compound of that add with hydrocar- Trans, 1826. Part 3. See Oil of Wine. 
boo 18 formed, differing from all known sub- Messrs Dumas and BouUay state the com- 

Itancesi, and whicb, poawensing add properties, position of sulphovinic acid, as analysed in 

and combining with salifiable bases to pro* combination with baryta, to 



ACID 



96 



SULPHURIC. 



Sulphate of baryta* 


5&3 


Sulphurous acid^ 


141.65 


Caxi>on, 


11.32 


Hydrogen, 


1.46 


Water, 


19.31 



100.04 
The compoaition of the oily matter, brought 
to 100, would give 

Carbon, 88.37 

Hydrogen, 11.63 

100.00 
It is therefore oil of wine. Ibis being ad- 
mitted, the sulphovinate of baryta is repre- 
sented by one atom of hyposuljdbate, two 
atoms of oil of wine, and five of water ; or 
Hyposulphate of baryta, 66.4 
OU of wine, 12.26 

Water, 19.65 



100.30 

The authors then show that similar re- 
sults are obtained by analyzing the sulpho- 
vinates of copper and lead. 

ACID (SULPHURIC). Sulphuric acid 
was formerly obtained in this country by dis- 
tillation from sulphate of iron, as it still is in 
many parts abroad. Tlie fluid that is thus 
obtained is the German sulphuric acid, of 
which Bernhardt got siity-four pounds from 
six hundred wei^t of vitriol ; and on the 
other hand, when no water had been pre- 
viously poured into the receiver, fifty-two 
pounds only of a dry concrete add. This 
add was formerly called glacial oil ofvitrioL 

It was shown by Vogri, that when this 
fuming add is put into a glass retort, and 
distilled by a moderate heat into a receiver 
cooled with ice, the fuming portion comes 
over first, and may be obtained in a solid state 
by stopping the distillation in time. This 
constitutes absolute sulphuric add, or add 
entirely void of water. It is in silky fila- 
ments, tough, difficult to cut, and somewhat 
like asbestos. Exposed to the air, it fiimes 
strongly, and gradually evaporates. It does 
not act on the skin so rapidly as concentrated 
oil of vitriol. Up to 66^ it continues solid, 
but at temperatures above this it becomes a 
colourless vapour, which whitens on contact 
with air. Dropped into water in small quan- 
tities, it exdtes a hissing noise, as if it were 
red-hot iron ; in larger quantities it produces 
a species of explosion. It is convertible into 
ordinary sulphuric add, by the addition of 
water. It dissolves sulphur, and assumes a 
blue, green, or brown colour, according to 
the proportion of sulphur dissolved. The 
spedfic gravity of the black fuming sulphu- 
ric acid, prepared in large quantities from 
copperas at Nordhaunen, is 1.896. 

The ordinary liquid acid of Nordhatisen is 
brown, of variable density, and boils at 100^ 
or 120^ F. One part of it evaporates in 



dense fumes, and the remainder is fbund to 
be common oil of ritrioL The above solid an- 
hydrous add has a spedfic gravity of 1.97 at 
68^^ F. ; at 7T* it remains fluid, and is less 
visdd than oil of ritriol. Hiere is a little 
sulphurous add present in that of Nordhau- 
sen, but it is acddental, and not essential to 
its constitution. The anhydrous add makes 
a red solution of indiga In the Journal of 
Sdence, xix. 62. I published the result of 
some experiments which I made to deter- 
mine the nature of the solid add. lYie brown 
liquid acid had a specific gravity of 1.842, 
When distilled from a retort into a globe sur- 
rounded with ice, a v^ite solid sublimate was 
recdved. When this sublinute was exposed 
to the air, it emitted copious fumes of sul- 
phuric (not sulphurous) add. It burned 
holes in paper with the rapidity of a red-hot 
iron. By dropping a bit of it into a poised 
phial containing water, and stoppering in- 
stantly, to prevent the ejection of liquid by 
the explosive ebullition that ensues, I got a 
dilute add containing a known portion of 
the solid acid, from the specific gravity of 
which, as well as its saturating power, I de- 
termined the constitution of the solid add to 
be the anhydrous sulphuric ; or a compound 
of two by wdg^t of sulphur, and three of 
oxygen. M. Gmelin states, in the Annales 
de Chimie et de Physique for June 1826, 
that on distilling sulphuric add, if we change 
the recdver at the instant when it is filled with 
opaque vapours, and cover the new recdver 
with ice, we shall obtain anhydrous sulphu- 
ric add, which is deposited in crystals on the 
inside of tiie vessel, and a less dense liquid 
add which remains in the retort. He su]>- 
poses, that during the distillation the sulphu- 
ric add is divided into two porticms, one of 
which gives up its water to the other. 

The sulphuric add made in Great Britain 
is produced by the combustion of sulphur in 
contact with a little nitre. 

The following ingenious theory of its for- 
mation, was first given by MM. Clement and 
Desormes. Hie burning sulphur or sul- 
phurous add, taking from the nitre a portion 
of its oxygen, forms sulphuric add, whidi 
unites with the potash, and displaces a little 
nitrous and nitric adds in vapour. These 
vapours are decomposed by the sulphurous 
acid into nitrous gas, or deutoxide of aaote. 
This gas, naturally little denser than air, and 
now expanded by the heat, suddenly rises to 
the roof of the chamber ; and might be ex- 
pected to escape at the aperture there, whidi 
manufacturers were always obliged to leave 
open, otherwise they found the addification 
would not proceed. But the instant that ni- 
trous gas comes in contact with atmospherical 
oxygen, nitrous add vapour is formed, which 
bdng a very heavy aeriform body, imroedi- 
atdy predpitates on the sulphurous flame, 
and converts it into sulphuric add; while 



ACID 



97 



SULPHORIC. 



ttael^ rennbing the slate of nitrons gas, re- 
ascends for a new charge of oxygen, again to 
redescend and transfer it to the flvning sul- 
phur. Thus we see^ that a small volume of 
nitrous yapour, by its alternate metamor- 
. f iboe cs into the states of oxide and add, and 
its conse({uent interchanges, may be capable 
of ncidilying a great quantity o£ sulphur. 

This beautiful theory received a modifies^ 
tkm firom Sir H. Davy. He found that nitrous 
gas had no action on sulphurous gas^ to con- 
vert it into sulphuric add, unless water be 
present. With a tmaU proportion of water, 
4 vidumes of sulphurous add gas, and 3 of 
nitrous gas, are condensed into a crystalline 
•olid, which is instantly decomposed by aMm- 
dance of water : oil of vitriol is formed, and 
nitrous gas given -oS^ which with contact of 
«ir becomes nitrous add gas, as above de- 
scribed. Hie process continues, according to 
the same prindple of combination and de- 
.^imposition, till the water at the bottom of 
the chamber is become strongly acid. It is 
.fint concentrated in large leaden pans, and 
afterwards in glass retorts heated in a sand 
bath. Flaiinum alembics, placed within pots 
of cast-iron of a corresponding shape and 
capadty, have been lately substituted in many 
manufiictories for glass, and have been found 
to save fuel, and quicken the process of con- 
centration. 

Dr Henry describes a peculiar substance, 
produced, during very cold weather, in the 
leaden pipe by which the foul air of a sul- 
phuric add chamber was carried away. It 
. was a solid resembling borax. It became soft 
and pasty in a warm room, and gradually a 
thick liquid of sp. gr. 1.831 floated over the 
solid pert. The crystalline part Dr Henry 
oonsiderB as probably the same compound as 
MM. Clement and Desormes obtained by 
mingling sulphurous add, nitrous gas, at^ 
.moqpheric ur, and aqueous vapour ; and he 
thinks its constitution is probably 

5 atoms sulphuric add, - 25.00 
1 atom hyponitrous add, - 4i.7d 

5 atoms water» - - 5,^25 



35.375 
AniuofPkiL XL 36a 
The proper mode of burning tlie sulphur 
with the nitre, so as to produce the greatest 
quantity of oil of ritriol, is a problem, con^ 
ceming which chemists hold a variety of opi- 
nions. M. Tlienard describes the following 
as the besL Near one of the sides of the 
leaden chamber, and about a foot above its 
bottom, an iron plate, furnished with an up- 
right border, is pieced horizontally over a 
furnace, whose chimney passes across, under 
the bottom of the chamber, without having 
any connexion with it. On this plate, which 
is enclosed in a little chamber, the mixture of 
sulphur and nitre is laid. Hie whole bdng 
shut up, and the bottom of the laige chamr 



ber covered with water, a gentle (Ire is kindled 
in the furnace. The sulphur soon tidies fire, 
and gives birth to the products described. 
When the combustion is finished, which is 
seen through a little pane adapted to the trap- 
door of the chamber, this is opened, the sul- 
phate of potash is withdrawn, and is replaced 
by a mixture of sulphur and nitre. The air 
in the great chamber is meanwhile renewed 
by opening its lateral door, and a valve in 
its opposite side. Then, after closing these 
openings, the furnace is lighted anew. Suc- 
cessive mixtures are thus burned till the arid 
acquires a specific grerity of about 1.390, 
taking care never to put at once on the plate 
more sulphur than the air of the chamber can 
acidify. The acid is then withdrawn by stop- 
cocks, and concentrated. 

The ordinary form of a sulphuric add lead 
diamber is the parallelopiped ; and its dimen- 
sions about seventy feet long, ten or twelve 
high, and sixteen wide. At the middle 
height of one end a small oven is built up, 
with a cast-iron sole, baring a large lead 
pipe, ten or twelve inches diameter, proceed- 
ing from its arched top into the end of the 
lead chamber. On the sole the sulphur is 
burned, the combustion bdng aided, when 
necessary, by beat applied from a little fm'- 
nace below it Above the flaming sulphur 
a cast-iron basin is supported in an iron 
frame^ into which the nitre, equal to one- 
tenth of the sulphur, is put, with a little sul- 
phuric add. The combustion of the sulphur 
is r^ulated by a sliding door on the oven. 
In the roof of the remote end of the large 
chamber, a small orifice is left for the escape 
of the atmospherical azote, and other incon- 
densable gases. This apparatus is used for 
the continuous process. But there is an- 
other, or that of the iniermitling combustion, 
which is worthy of notice. Large flat trays, 
containing the sulphur and nitre, are intro- 
duced into the interior of the chaniber, or 
into* the oven, and fire is applied to the ma- 
terials. When the sulphur is burned, and 
the chamber is replete with sulphurous and 
nitrous adds, the steam of water is thrown 
in, in determinate quantity, by a small pipe 
at the side. This causes a tumultuous mo- 
tion among the gases and the atmospheric 
oxygen, which favours the mutual reaction. 
As the steam condenses, the sulphuric add 
falls with it. After some time, the chamber 
is aired by Opening valves of communication 
with the external atmosphere. The operation 
is then commenced anew. 

Instead of using nitre, nitrous gas, disen- 
gaged from nitric add by sugar or saw-dust, 
is introduced into the chamber containing the 
I fumes of burning sulphur, whereby the che- 
mical reaction above described is produced ; 
and then steam is thrown in to complete the 
process, and condense the sulphuric add. 



ACID 98 SULPHURIC. 

Tbe bottom of the lead cbaiAber aboutd Mott deeidied advmntigea. Each dumibflr b 
never be coTcred with pure water, but even thus maintained at a temperature nearly uni- 
in the first operation with a dilute add, in- form, which saves the injuries often donetotfae* 
troduced on purpose. When nitrous add plates of lead, by the too frequent and abrupt 
comes into contact with vrater and an excess expansions and contractions in the intermiu 
of atmospheric oxygen, it is converted into ting plan. The nitre basins and trays are, 
nitric add and nitrous gas. This aeriform for the same reason, not so rapidly wasted, 
body gets more oxygen, and changes to nit- The quantity of acid obtained is greater, by 
rous add, and tliereafter to nitric Hence, nearly a third, in a given time, with an equal 
a chamber with its bottom covered with water, capadty of chambers. The wages of labour 
will, in some cases, fail in produdng any is also less, as well as the fuel requisite lior 
.sulf^uric add at all. Water, moderately burning the sulphur. Indeed, the sulphur- 
charged with sulphuric and sulphurous adds, pan or sole needs heating only at the com- 
prevents the transition of the nitrous into mencement Tlie dose of nitre is reduced 
, nitric add, and allows the process of addifi- to 8 per cent. 
. cation of the sulphur to go on freely. But nothing is easier than to combine the 

MM. Fayen and Cartier disengage the two systems, and to render these chambera 

nitrous gas in the midst of the burning sul- intermittent, by gradually obstructing the in- 

rpbur, from a mixture of nitric add and starch gress of air into the combustion oven, then 

contained in platinum basins. The main ol>- intercepting it altogether, and throwing in 

.jection to this process, is the difficulty of find- steam, condensing the add vapours, and 

ing a market for the oxalic add produced. thereafter ventilating the air of tbe chan»- 

Other chemists find, that it answers to in- bers. 
troduce the vapour of nitric add into the The following details are extracted from a 

fumes of the burning sulphur, which con- paper on sulphuric add, which I published in 

. verts it into nitrous add ; but the simplest the 4Ah volume of the Journal of Sdence and 

mode of effecting this object, is by the cast^ the Arts. 

iron basin placed over the burning sulphur, Commerdal sulphuric add often contains 

as already described. from one-half to three quarters of a part in 

In burning the sulphur, care should be the hundred, of solid saline matter fordgn to 
taken that it does not rise in flowera by mere its nature, lliese fractional parts consist of 
sublimation ; to prevent which, the ingress sulphate of potash and lead, in the prcqpor- 
of air should be proportional to the heat of tion of four of the former to one of the lat- 
tbe oven plate in the continuous process, ter. Tbe ordinary acid sold in the shops 
The presence of sulphur in the add would contains often three or four per cent of sa- 
. occasion great losses, were it not allowed to line matter. Even more is occasionally in- 
subside by repose ; for in the concentration troduced, by the employment of nitre, to ro- 
of the sulphuric add by beat, the sulphur move the brown colour given to the add by 
would convert it into the sulphurous add, caibonaceous matter. The amount of these 
which would be dissipated in the air. adulterations, whether acddental or fraudu- 

Tlie following form of apparatus, as used lent, may be readily determined by evapo- 

by MM. Payen and Cartier, has been lately rating in a small capsule of porcelain, or 

described in the AnnaUs de VlnduUrie, U L rather platinum, a definite wdght of the add. 

It consists of a combustion oven, which com- The platinum cup, placed on the red dnden 

.municates with a first chamber ; this ftends of a common fire, will give an exact result 

forward its gases into a second, which leads in five minutes. If more than five grains of 

to a third, and this to a fourth when neces- matter remain from five hundred of add, we 

sary. But the fourth chamber does not im- may pronounce it sophisticated. 

, mediately support the chimney, but commu- Distillation is the mode by which pure oil 

nicates with it by a long sloping canal. In of vitriol is obtained. This process is des- 

the first chamber the add is kept up at cribed in chemical treatises as both diflicult 

about 1.500 ; in the second at 1.370 ; and and haxardous ; but, since adopting the fol- 

in the third at 1.130. Tbe floora of the so- lowing phui, I have found it perfectly safe 

vera! chambers rise in succession, so that, by and convenient. I take a plain glass retort, 

.means of syphons, a portion of the add may capable of holding from two to four quarts of 

be drawn from the second to the first, and water, and put into it about a pint measure 

from the third to the second, in proportion of the sulphuric add, (and a few fragments of 

. as the add is let off out of the first for the glass), connecting the retort with a large glo- 

purpose of concentration. Steam is also in- bular recdver, by means of a glass tube four 

jected constantly into the terminal canal, and feet long, and from one to two inches in dia- 

occasionally into each of the chambers, to fa- meter. The tulie fits very loosely at both ends. 

■cilitate the condensation of add. Hie retort is pUced over a charcoal fire, and 

In comparing this and other forms of con- the flame is niade to play gently on its bot- 

tinuous apparatus, with those where tbe com- torn. When the add begins to boil smartly, 

bustion is made to intermit, it obviously pre- sudden explosions of dense vapour rush forth 



ACID 



99 



SULPHURIC. 



to tsme^ which would infiiUibly 
small Tessels. Here, however, these 
-espttDsioiis are safely permitted, by the large 
capacity of the tetmrt and recdver, as well as 
by the easy communication with the air at 
both ends of -the adopter tube. Should the 
• reCort» indeed, be exposed to a great intensity 
of flame, the vapour will no doubt be gene- 
rated with incoercible rapidity, and break the 
-apparatus. But this accident can proceed 
-ooly firom gross imprudence. It resembles, 
io suddenness, the explosion of gunpowder, 
and illustrates admirably Dr Black's obser^ 
vatioo, that, but for the great latent heat of 
ateam, a mass of water, powerfully heated, 
would explode on reaching the boiling tem- 
peratore. I have ascertained, that the spe- 
cific caloric of thfe vapour of sulphuric add 
is very small, and hence the danger to whidi 
rash operators may be exposed during its 
'distiUation. Hence, also, it is unnecessary 
to surround the receiver with cold water, as 
when alcohol and most other liquids are dis- 
tilted. Indeed the application of cold to the 
bottom of the receiver generally causes it, in 
the present operation, to crack. By the above 
method, I have made the concentrated oil of 
'vitriol flow over in a continuous slender 
stream, without the globe becoming sensibly 
hot 

I have frequently boiled the distilled add 
till only one-half remained in the retort; yet 
St the temperature of 6(F F^renhdt, I have 
never found the spedfic gravity of add so 
concentrated to exceed 1.8455. It is, I be- 
lieve, more exactly 1.8452. The number 
1.850, which it has been the fashion to assign 
for the demity of pure oil of ritriol, is un- 
doubtedly very erroneous, and ought to be 
corrected. Genuine commercial add should 
never surpsss 1.8475 : when it is denser, we 
may infer sophistication, or negligence, in 
the manulkcture. 

'Die progressive increase of its density, with 
saline contamination, will be shown by the 
following experiments :-*-To 4100 grains of 
genuine commerdal add (but concentrated 
to only 1.8350), 40 grains of dry sulphate of 
potash were added. When the solution was 
completed, the spedfic gravity at 60^ had 
become 1.8417. We see that at these den- 
sities the addition of 0.01 of salt increases 
the spedfic gravity by about 0.0067. To 
the above 4140 grains other 80 grains of 
sulphate were added, and the spedfic gravity, 
after solution, was found to be 1.8526. We 
percdve that somewhat more salt is now re- 
quired to produce a proportional increase of 
density ; 0.01 of the former changing the 
latter by only 0.0055. Five hundred grains 
of this acid bdng evaporated in a platinum 
oqMule^ left I6§ grains, whence the compod* 
tion w a s 



Sulphate of potash, with a litde sulphate of 

lead, .... aaO 

Water of dilution, . - 5.3 
Oil of vitriol of 1.8485, - 91.4 

100.0 
Thus, add of 1.8526, which in commeree 
would have been accounted very strong, con- 
tained little more than 91 per cent of genu- 
ine add. 

Into the last add more sulphate of potash 
was introduced, and solution bdng favoured 
by digestion in a moderate heat, the spedfic 
gravity became, at 60^^, 1.9120. Of this 
compound, 300 grains, evaporated in the 
platinum capsule, left 41 grsins of gently 
ignited saline matter. We have^ therefore* 
nearly 14 per cent. On the spedfic grsvity 
in this interval, an increase of 0.0054 was 
efl^ed by aOl of sulphates Hiis liquid 
was composed of saline matter, . 14 
Water of dilution, - . 4.7 

Oil of vitriol of 1.8485, - 81.3 

100.0 
The general proportion between the density 
and impurity may be stated at 0.0055 of tlie 
fbrmer, to 0.01 of the hrtter. 

If from genuine oil of vitriol, containing J 
of a per cent of saline matter, a considerable 
quantity of add be distilled off, what remains 
in the retort will be found very dense. At 
the spedfic gravity 1.865, such add con- 
tains 3i of solid salt in the 100 parts. The 
rest is pure concentrated add. From such 
heavy acid, at the end of a fiew days, some 
minute crystsls will be depositedf aflter which 
its spedfic grarity becomes 1.860, and its 
transparency is perfect. It contains about 
8f per cent of saline matter. . Hence, if the 
chemist employ for his researches, an add 
which, though originally pretty genuine, has 
been exposed to long ebullition, he will fall 
into great errors. From the last experiments 
it appears, that concentrated oil of vitriol can 
take up only a little saline matter in compa- 
rison with that which is somewhat dilute. 
It is also erident, that those who trust to 
spedfic gravity alone, for asceriaioing the 
value of oil of vitriol, are liable to great im- 
positions. 

The saline impregnation exerdses an im- 
portant influence on all the densities at sub- 
sequent degrees of dilution. Thus, the heavy 
impure concentrated add, specific gravity 
1.8650, being added to water in the propor- 
tion of one part to ten, by wdght gave, after 
twenty-four hours, a compound whose sped« 
fie gravity was 1.064. But the most concen- 
trated genuine acid, as well as distilled add» 
by the same degree of dilution, namely 1 4- 
10, acquires the spedfic grarity of only 
1.0602, while that of 1.852, containing, as 
stated above, 3^ per cent of sulphate of pot- 
ash combined with add of 1.835^ gi^es, on 



ACID 



100 



SULPHURIC. 



^namiUur d3utioii» 1.056. • This-difif^rence, 
though yery obvious to good instruments, is 
inappreciable by ordinary commercial appi^ 
ratus. Hence tliis mode of ascertaining the 
value of an acid, recommended by Mr Dal- 
ton, is inadequate to detect a deterioration 
of even 8 or 9 per cent. Had a little more 
salt been present in the acid, the specific gra- 
vis of the dilute, in this case, would have 
equalled that of the genuine. On my aci^ 
dieter one per cent of deterioration could 
not fail to be detected, even by those igno- 
rant of science. 

The quantity of oxide, or raUier sulphate 
of lead, which sulphuric acid can take up, is 
much more limited than is commonly ima- 
gined. To the concentrated oil of vitriol I 
udded much carbonate of lead, and after di^ 
gestion by a gentle heat, in a dose vessel, for 
twenty-four hours, with occasional agitation^ 
its specific grarity, when taken at 60^, w^s 
«c»rcely greater than before the experiment. 
It contained about 0.005 of sulphate of lead. 

The quantity of water present in 100 parts 
of concentrated and pure oil of vitriol, seems 
to be pretty exactly 18.46. 

In the experiments executed to determine 
the relation between the density of diluted 
oil of ritriol and its acid strength, I em^ 
ployed a series of phials, numbovd with a 
diamond. Into each phial, recently boiled 
add, and pure water, were mixed in the suc- 
cessive proportions of 99 -^ 1, 98 -^ 2, 
.97 <4- 3, &c. through the whole range of di- 
gits down to 1 acid -^ 99 water. The phials 
.were occasionally agitated during 24 hours, 
after which the spedfic gravity was taken. 
The add viras genuine and well concentrated. 
Its specific gravity was 1.8485. Some of 
the phials were kept with thdr add contents 
for a week or two, but no further change in 
^e density took place. Tlie strongest pos- 
sible dislUted add was employed for a few 
points, and gave the jsame results as the 
other. 

Of the three well-known modes of ascer- 
taining the specific gravity of a liquid, name- 
ly, that by Fahrenhdt's hydrometer; by 
weighing a vessel of known capadty filled 



,with it; and by poising aglaas ball, su^pcn^- 
ied by a fine pladna wire from the arm of a 
delicate balance— I deddedly prefer the last. 
The oorrosiveness, visddity, and wdght of 
oil of vitriol, render the first two methods 
indigible ; whereas, by a ball floating in a 
liquid, of which the spedfic gravity does not 
difiTer much from its own, the balance, litda 
loaded, retains its whole sensibility, and will 
give the most accurate consistency of results. 

In taking the spedfic gravity of concen- 
trated or slightly diluted add, the temperature 
must be minutely regulated, because, from 
the small spedfic heat of the acid, it is easily 
affected, and because it greatly influences the 
.density. On removing the thermometer, it ' 
wUl speedily rise in the air to 75^ or 80^ 
though the temperature of the apartment be 
only 60^. Afterwards it will slowly &11 to 
perhaps 60^ or 629. If this thermometer, 
having its bulb covered with a film of dilute 
acid, (from absorption of atmospheric moisr> 
ture), be plunged into a strong add, it will 
instantly rise 10°, or more, above the real 
temperature of the liquid. Ihis source of 
embarrassment and occasional error is obvi- 
ated by wiping the bulb after every immer- 
sion. An elevation of temperature^ equal to 
IQo Fahr. diminishes the density of oil of 
vitriol by 0.005 ;— 1000 parts being heated 
from 60° to 2129, become 1.043 in volume^ 
as I ascertained by very careful experimeot& 
The spedfic gr.^vity, which was 1.848, be- 
comes only 1.772, bdng the number corres- 
ponding to a dilution of 14 per cent of water. 
The visddity of oil of vitriol, which below 
50° is such as to render it difficult to deter- 
mine the spedfic gravity by a floating ball, 
diminishes very rapidly as the temperature 
rises, evindng that it is a modification of cov 
hesive attraction. 

Tlie following Table of Densities, corra»> 
ponding to degrees of dilution, was the re^ 
suit, in each point, of a particular experiment, 
and was moreover verified, in a number of 
its terms, by the further dilution of an add» 
previously combined with a known propor- 
tion of water. The balance was accurate 
and sensible. 



ACID 



101 



SULPHURIC. 



TABLE of the QuantUy of Oil of VUriol and Dry Sulphuric Acid in 100 
parts ofDUtUe, at different Densities, by Da-Uftf. 



Uqoid. 


Sp. Or. 


Dry. 


Liquid. 


Sjp.Gr. 


Dry. 


TJqoU. 


S^ Or. 


Dry. 


100 


1.8485 


81.54 


66 


1.5503 


5a82 


32 


1.2334 


26.09 


99. 


1.8475 


80.72 


65 


1.5390 


5aoo 


31 


1.2260 


25.28 


98 


1.8460 


79.90 


64 


1.5280 


52.18 


30 


1.2184 


24.46 


97 


1.8439 


79.09 


63 


1.5170 


51.37 


29 


1.2108 


23.65 


96 


1.8410 


7a 28 


62 


1.5066 


50.55 


28 


1.2032 


22.83 


95 


1.8376 


77.46 


61 


1.4960 


49.74 


27 


1.1956 


22.01 


94. 


1.8336 


76.65 


60 


1.4^60 


4a 92 


26 


1.1876 


21.20 


93 


1.8290 


75.83 


59 


1.4760 


4aii 


25 


1.1792 


20.38 


92 


1.8233 


75.02 


58 


1.4660 


47.29 


24 


1.1706 


19.57 


91 


r.8179 


74.20 


57 


1.4560 


46.48 


23 


1.1626 


ia75 


90 


1.8115 


7a39 


56 


1.4460 


45.66 


22 


1.1549 


17.94 


89 


1.8043 


72.57 


55 


1.4360 


44.85 


21 


1.14^ 


17.12 


88 


1.7962 


71.75 


54 


1.4265 


44.03 


20 


1.1410 


1&31 


87 


1.7870 


70.94 


53 


1.4170 


4a22 


19 


1.1330 


15.49 


86 


1.7774 


70.12 


52 


1.4073 


42.40 


18 


1.1246 


14.68 


85 


1.7673 


69.31 


51 


1.3977 


41.58 


17 


1.1165 


ia86 


S^ 


1.7570 


68.49 


50 


I.ijOOv 


40.77 


16 


1.1090 


iao5 


83 


1.7465 


67.68 


49 


1.3788 


39.95 


15 


1.1019 


12.23 


82 


1.7360 


66.86 


48 


1.3697 


39.14 


14 


1.0953 


10.41 


81 


1.7245 


66.05 


47 


1.3612 


3a32 


13 


1.0887 


11.60 


80 


1.7120 


65.23 


46 


1.3530 


37.51 


12 


1.0609 


9.78 


79 


1.6993 


64.42 


45 


J.OVvi' 


36.69 


11 


1.0743 


a97 


78 


1.6870 


6a 60 


44 


1.3345 


35.88 


10 


1.0682 


a 15 


77 


1.6750 


62.78 


43 


1.3255 


35.06 


9 


1.0614 


7.34 


76 


1.6630 


61.97 


42 


1.3165 


34.25 


8 


1.0544 


6.52 


75 


1.6520 


61.15 


41 


1.3080 


3a43 


7 


1.0477 


5.71 


74 


1.6415 


60.34 


40 


1.2999 


32.61 


6 


1.0405 


4.89 


73 


1.6321 


59.52 


39 


1.2913 


31.80 


5 


1.0336 


4.08 


72 


1.6204 


5a71 


38 


1.2826 


30.98 


4 


1.0268 


a26 


71 


1.6090 


57.89 


37 


1.2740 


30.17 


3 


1.0206 


2.446 


70 


1.5975 


57.08 


36 


1.2654 


29.35 


2 


1.0140 


1.63 


69 


1.5868 


56.26 


35 


1.2572 


2a54 


1 


1.0074 


0.8154 


68 


1.5760 


55.45 


34 


1.2490 


27.72 








67 


l.dOxO 


54.63 


.S3 


1.2409 


26.91 









In order to compare the densities of the 
preceding dilute acid, with those of distilled 
Mid again ooncentntfed acid, I mixed one 
part of the latter with nine of pure water, 
and, after agitation, and a proper interval 
to ensure thorough combination, I found its 
specific gravity, as above, 1.0682: greater 
density indicates saline contamination. 
■ Dilute acid, having a specific gravity ^ 
1.6321, has suffered the greatest condensa- 
tion; 100 parts in bulk have become 92.14. 
If other more or less acid exist in the com- 
pound* the volume will be increased, ^hat 
reason can be assigned for the maximum 
Qondensation occurring at this particular term 
cif dilution? The above dilute add consists 
of 73 per cent of oil of vitriol, and 27 of 
water. But 73 of tlie former contains, by this 
t^le, 59.52 of dry add, and ia48 of water. 
Meoce 100 of the dilute add consist of 
59.52 of dry add, + 1^^ X 3 = 40.44 of 
^ater s=: 99.96 ; or it is ji compound of one 
atom of dry add, ¥rith three atoms of yrater. 



Dry sulphuric add consists of three atoms 
of oxygen united to one of sulphur. Here . 
each atom of oxygen is assodated with one of 
water, forming a symmetrical arrangement. 
We may therefore infer, that the least devia.- 
tion from tiie above definite proportions must 
impair the balance of the attractive forces, 
whence they will act less efficaciously, and 
therefore produce less condensation. 

The very minute and patient examination 
which I was induced to bestow on the table 
of spedfic gravities, disclosed to me the 
general law pervading the whole, and con- 
sequently the means of inferring at once the 
density from the degree of dilution, . as also 
of solving the inverse proportion. 
, If we take the specific gravity, correspond- 
ing to 10 per cent of oil of vitriol, or 1.0682 
as the root ; then the specific gravities, at the 
successive terms of 20, 30, 40, &c. wiU be 
the successive powers of that root The terms 
of dilution are like logarithms, a series of 
numbers in arithmetical progressioo» corses* 



ACID 



102 



SULPHURIC 



ponding to another aerie% namelj, the spe- 
cific gravities in geometrical progression. 

The simplest logarithmic formula which I 
hare been able to contrive is the following : 

Log. Sss _. , where S is the specific gravity, 

and a the per-centage of add. 

And a s= Log. S X 350. 

In common language the two rules may 
be stated thus : 

Problem 1st. To find the proportion of 
oil of vitriol in dilute acid of a given specific 
gravity. Multiply the logarithm of the spe- 
cific gravity by 350, the product is directly 
the per-centage of add. 

If the dry add be sought, we must multi- 
ply the logarithm of the spedfic gravity by 
285, and the product will be the answer. 

Problem 2d. To find the specific gravity 
corresponding to a given proportion of add. 
Multiply the quantity of add by 2, and 
divide by 700; the quotient is the logarithm 
of the specific gravity. 

Table of Distilled Sulphuric Add for the 
higher points, bdow which it agrees with 
the former Table. 

Dry JdtL 
81.63 
77.55 
7a47 
69.39 
65.30 
6L22 

Sulphuric add strongly attracts water, 
which it takes from the atmosphere very 
rapidly, and in larger quantities, if suffered 
to remain in an open vessel, imbibing one- 
third of its wdght in twenty-four hours, and 
more than six times its wdght in a twdve- 
month. If four parts by wdght be mixed 
with one of water at 50°, they produce an 
instantaneous heat of 300° F. ; and four 
parts raise one Of ice to 212° : on the con- 
trary, four parts of ice, mixed with one of 
add, sink the thermometer to 4° below 0. 
It requires a great d^ree of cold to freeze 
it; and if diluted with half a part or more of 
water, unless tlie dilution be carried very far, 
it becomes more and more difiScult to con- 
geal ; yet at the spedfic gravity of 1.78, or 
a few hundredths above or lielow this, it may 
be frosen by surrounding it with melting 
snow. Its congelation forms regular pris- 
matic crystals with six sides. Its boiling 
point, according to Bergman, is 540° ; ac- 
cording to Dalton, 590°. 

Sulphuric add consists of three prime 
equivdents of oxygen, one of sulphur, and 
one of water; and by wdght, therefore, of 
3.0 oxygen + 2.0 sulphur -f- 1.125 water 
as 6.125, which represents the prime equi- 
valent of the concentrated h'quid add ; while 
3 4- 2 as 5, will be that of the dry add. 



Uqwdjtcid in IQO. 


4». Gr, 


• 100 


1.846 


95 


1.834 


90 


1.807 


85 


1.764 


80 


1.708 


75 


L650 



Pure sulphuric add is without sqaell and 
colour, and of an oily consistence. Its ac- 
tion on litmuses so strong, that a single drop 
of acid will give to an immense quantity of 
water the power of reddening. It is % most 
violent caustic ; and has sometimes been ad- 
ministered with the most criminal purposes. 
The person who unfortunately swallows it, 
speedily dies in dreadful agonies and convul- 
sions. Chalk, or common carbonate of mag- 
nesia, is the best antidote for this, as well aa 
for the strong nitric and muriatic adds. 

When transmitted through an ignited por- 
celdn tube of one-fifth of an inch diameter^ 
it is resolved into two parts of sulphurous 
add gas, and one of oxygen, gas, with water- 
Voltaic electridty causes an evolution of sul- 
phur at the negative pole ; whilst a sulphate 
of the metallic wire is formed at the pokitive. 
Sulphuric add has no action on oxygen gas 
or air. It merely abstracts their aqueoua 
vapour. 

If the oxygenized muriatic add of M. 
Thenard be put in contact with the sulphate 
of silver, there is immediately formed in- 
soluble chloride of diver, and oxygenized 
sulphuric add. To obtain sulphuric add 
in the highest degree of oxygenation, it is 
merely necessary to pour baryte water into 
the above oxygenized add, so as to predpi- 
tate only a part of it, leaving the rest in 
union with the whole of the oxygen. Oxy- 
genized sulphuric add partially reduces the 
oxide of silver, occasioning a strong effer- 
vescence. See Acid. 

All the simple combustibles decompose 
sulphuric add, with the assistance of heat. 
At about 400^ Fahr. sulphur converts sul- 
phuric into sulphurous add. Several metals 
at an elevated temperature decompose this 
add, with evolution of sulphurous add gas, 
oxidizement of the metel, and combination of 
the oxide with the undecomposed portion of 
the acid. 

Sulphuric add is of very extensive use in 
the art of chemistry, as well as in metallorgyy 
bleaching, and some of the processes for dye- 
ing; in medidne it is given as a tonic and 
stimulant, and is sometimes used externally 
as a caustic. 

The combinations of this add with the 
various bases are called sulphates, and most 
of them have long been known by various 
names. With ba^te it is found native and 
neariy pure» in various forms. (See Hbaty 
Spar,) It may be artificially formed by drop- 
ping a solution of an alkaline sulphate into- 
the solution of muriate or nitrate of baryta. - 
It forms a white powder which suffcre no 
change by the action of the air, and is there- 
fore sometimes used in water-colour painting. 

It consists, according to Dr Wollaston, of 
5 parts of dry add, and 9.75 of baryta. It 
requires 43,000 parts of water to dissolve it 
at 60°. 



ACID 



103 



SULPiHUftIC 



So^ihate of strontia has a coDsidenblt 
memblance to that atbwyttL in its propertiea. 
It is found native in considerable quantities 
at Auat Pnssnge and other places in the 
ncigfabouriiood of Bristol It requires 3840 
ports of boiling water to dissolve it. 
Its oomposition is 5 acid -f- ^^ base- 
Sulphate of potash, formerly vUriohled 
taaUoTf crystallises in hexaedral prisms, ter- 
minated by hexagonal pyramids, but suscep- 
tible of variations. ItscrystaHisationbyquidL 
cooling is confused. Its taste is bitter, acrid, 
and a little saline. It is soluble in five parts 
of boiling water, and sixteen parts at 00°. 
In the fire it decrepitates, and is fusible by a 
strong beat. It is decomposable by chamwl 
■t m hi^ temperature. It may be prepared 
by direct mixture of its component parts; 
bat the usual and cheapest mode is to ignite 
the addnlous sulphate left after distilling ni- 
tric add. The nU poltfchrtU of old dispen- 
aatories, made by deflagrating sulphur and 
nitre in a crudfaie^ was a compound of the 
svlphate and sulphite of potash. The ad- 
dnloua sulphate is sometimes employed as a 
Ausy and likewise in the manufacture of alum. 
In medidne the neutral salt is sometimes used 
as a mild cathartic. 

It consists of 5 add -f- base ; but there 
is a compound of the same constituents, in 
the proportion of 10 add -|- 6 potmh, called 
the bi-snlphate. 

Sulphate of soda is the well known Glau" 
h€r*a tall* It is commonly prepared from the 
residuum left after distilbig muriatic acid, 
the superfluous add of which may be ex- 
pelled by ignition ; and is likewise obtained 
in the manufacture of the muriate of am- 
monia. (See Ammonia.) It existe in large 
quantities under the sur&ce of the earth in 
aome countries, as Penia, Bohemia, and 
Switaeriand ; is found mixed with other sub- 
-stanoes in minenl springs and aea water ; and 
sometimes eflBoresces on walls. Sulphate of 
soda is bitter and saline to the tsste. It is 
aohiMc in 8.85 parts of cold water, and 0.8 
at a boiling heat ; it crystallizes in hexagonal 
prisma bevelled at the extremities, sometimes 
groofved longitudinally, and of very laige sise, 
when the quantity is great : theae efiloresoe 
completdy into a white powder if exposed to 
a dry air, or even if kept wrapped up in pa- 
per in a dry place; yet they retain suflident 
water of cfystallisation to undergo the aqu». 
ous ftision on exposure to heat, but by urg- 
ing the flre^ melt Baryta and strontia take 
its add from it entirely, and potash partially ; 
the nitric and muriatic adds, though they 
have a weaker affinity for its base, combine 
with a part of it when digested on it. Heat- 
ed with charcoal its add u decomposed. As 
a purgative its use is very general ; and it 
has been employed to ftimi^ soda. Pigot 
dee Oiames has made some experiments on 
it in fabgicatiBg glawt with sand, alone it 



would not succeed, but equal parts of car- 
bonate of lime, sand, and dried sulphate of 
soda, produced a clear, solid, pale yellow 



It is composed of 5 add -^ 4 base •f- 
1 1.25 water in crystals ; when dry, the former 
two primes are its constituents. 

A difference in the temperature at which 
a solution of sulphate of soda is evaporated, 
will cause the formation of the ordinary hy- 
drated crystals or anhydrous crystals, at plea- 
sure. When hydrated crystals of soda are 
carefully melted, a portion dissolves and a 
portion separates; the latter in an anhydrous 
state. 

Sulphate of soda and sulphate of ammom'a 
form together a triple salt. 

Sulphate of lime, teUniie, gypsum, plaster 
i^PariSj or sometimes alabaster, forms exten- 
fiive strata in various mountains. See Gyp:. 

SUM. 

It requires 500 parts of cold water, and 
450 of hot, to dissolve it When caldned, it 
decrepitates, becomes very friable and white, 
and heats a little witli water, vrith which it 
forms a solid mass. In this process it loses 
its water of crystallization. The caldned suK 
pluite is much employed for making casts of 
anatomical and ornamental figures; as one 
of the bases of stucco ; as a fine cement for 
making dose and strong joints between stone, 
and joining rims or tops of metal to glass; 
for making moulds for the Staffordshire pot- 
teries; for cornices, mouldings, and other 
ornaments in building. For these purposes,, 
and for bdng wrought into columns, chim- 
ney-pieces, and various ornaments, sbout eight 
hundred tons are raised^ annually in Deri^y- 
shire, where it is cslled alabaster. In Ame- 
rica it is laid on grass land as a manure. 

Ordinary crystallized gypsum consists of 
5 sulphuric add 4- 3.5 lime .^2.25 water-; 
the anhydrous variety wants of course the last 
ingredient 

Sulphate of magnesia is commonly known 
by the name of Epsom salt, as it was fui*- 
nished in conuderable quantity by the mine- 
ral water at that place^ mixed, however, with 
a considerable portion of sulphate of sods. 
It is afforded, however, in greater abundance, 
and more pure, from the bittern left after the 
extraction of salt fixnn sea water. It has like- 
vrise been found efflorescing on brick walls, 
both old and recently erected, and in small 
quantity in the ashes of coals. Hie capil- 
lary salt of Idria, found in silvery crystals 
mixed with the aluminous schbt in the mines 
of that place, and hitherto considered as a 
feathery alum, has been ascertained by Klap- 
roth to consist of sulphate of magnesia, mix- 
ed with a small portion of sulphate of iron. 
When pure it crystallizes in small quadran- 
gular prisms, terminated by quadrangular 
pyramids or dfedral summits. Its taste Js 
cod and bitter. It is very soluble^ requiring 



ACID 104 SULPHUROUS. 



pnly an equal wei^t of cold watar> and three- recently known, and it was fint attentifdy 
fourths its weight of hot. It effloresces in examined by Vauquelin. It may be made 
tbe air, though but slowly. If it attract mois- l^y dissolving pure alumina in pure sulphuric 
ture, it contains muriate of magnesia or of acid, heaUng them for some time, eraporaU 
)ime. Exposed to heat, it dissolves in its ing the solution to diyness, drying the reai<. 
own water of crystallization, and dries, but is duum with a pretty strong heat, redissolving 
not decomposed, nor fused, but with extreme it, and crystallizing. Its crystab are soft, 
difficulty. It consists, according to Berg- foliaceous, shining, and pearly; but these are 
man, of 33 add, 19 magnesia, 48 water. A not easily obtained without cautious evaporv 
very pure sulphate is said to be prepared in tion and refrigeration. They have an astrin- 
the neighbourhood of Genoa, by roasting a gent taste ; are little alterable in the air ; are 
pyrites found there, exposing it to the air in pretty soluble^ particularly in hot water; give 
a covered place for six months, watering it out their acid on exposure to a high tempe- 
occasionally, and then lixiviating. ratuie; are decomposable by combustible sub- 

Sulphate of magnesia is one of our most stances, though not readily ; and do not focm 
valuable purgatives ; for which purpose only a pyrophorus like alum, 
it is used, and for furnishing the carbonate <^ If the evaporation and desiccation directed 
magnesia. above be omitted, the alumina will remain 

It is composed of 5 add 4* ^^ magnesia supersaturated with add, as may be known 
-^ 7.875 water, iu the state of crystals. by its taste^ and by its reddening vegetable 

Sulphate of ammonia crystallizes in slen- blue. This is still more difficult to crystal* 
der, flattened, hexaedral prisms, terminated lize than the neutral salt, and frequently 
by hexagonal pyramids ; it attracts a little thickens into a gelatinous mass, 
nunsture from very damp air, particularly if A compound of addulous sulphate of alu- 
the add be in excess ; it dissolves in two parts mina with potash or ammonia has long been 
of cold and one of boiling water. It is not known by the name of Aldil See Aur* 
used, though Glauber, who called it his tecrei mina. 

ammoniacal $aU, vaunted its excellence in If this addulous sulphate or alum be dia- 
aasaying. solved in water, and boiled with pure alu- 

It consists of 5 add 4* ^ 1^ ammonia -4- mina, the alumina will become saturated with 
1. 125 water in its most desiccated state ; and its base, and fall down an insipid white pow* 
in its crystalline state of 5 add .^ 2. 125 am- der. This salt is completdy insoluble^ and 
monia 4- 3.375 water. is not deprived of its add by heat but at a 

If sulphate of ammonia and sulphate of very high temperature. It may be deoooH 
magnesia be added together in solution, they posed by long boiling with the alkaline or 
combine into a triple salt of an octaedral earth bases ; and several adds convert it into 
figure, but varying much ; less soluble than common alum, but slowly, 
either of its component parts; unalterable in Sulphate of zirconia may be prepared by 
the air ; undergoing on the fire the watery adding sulphuric add to the earth recently 
fusion ; after which it is decomposed, part of predpiteted, and not yet dry. It is sometimea 
the anunonia flying off, and the remainder in small needles, but commonly pulverulent; 
subliming with an excess of acid. It con- very friable; insipid; insoluble in water, un- 
tains, according to Fourcroy, 68 sulphate of less it contain some add ; and easily deiXMn- 
magnesia and 32 sulphate of ammonia. posed by heat. 

Sulphate of gludna crystallizes with diffi. ACID (SULPHUROUS). Hiis add is 
culty, its solution readily acquiring and re- formed by the ordinary combustion of sul- 
taining a syrupy consistence ; its taste is sweet, phur in the open air : but it can be obtained 
and slightly astringent ; it is not alterable in most purely and conveniently by digesting 
the air; a strong beat expels its acid, and mercury in sulphuric add, with heat, in a re- 
leaves the earth pure ; heated with charcoal tort. Tbe metal beeomes oxidised, and su^ 
it forms a sulphuret ; infusion of galls forms phurous add gas is disengaged with efferp- 
a yellowish-white precipitate with its solu* vescence. M. Berthier hi» recently shown 
tion. that sulphurous add gas may be obtained 

Yttria is readily dissolved by sulphuric very pure, and abundantly, by heating a mix- 
add ; and as the solution goes on, the sul- ture of twelve or fourteen parts of sublimed 
phate crystallizes in small brilliant grains, sulphur, and a hundred parts of peroxide of 
which have a sweetish taste, but less so than manganese, in a glass retort. Tbe residue in 
sulphate of gludna, and are of a light ame- the retort is not a sulphuret of manganeae^ 
thyst-red colour. They require 30 parts of but a protoxide of that metal, mixdl with 
cold water to dissolve them, and give up thdr a little sulphate^ and sometimes a little sul- 
acid when exposed to a high temperature, phur.— ^nn. de Ckim. et de PAys. xxiv. 27& 
. They are decomposed by oxalic add, prus- Tbe gas may be collected over quicksilver, 
siate of potash, infusion of galls, and phos- or reodved into water, which, at the tempo- 
pbate of soda. rature of 6F, wUl absorb 33 times its bulk, 

Sulphate of alumina in its pure state is but or nearly an eleventh of its weight. 



ACID 



105 



HTPOSULPHUROUS. 



. Wftter thus nturated is intensely acid to 
the tsste^ and has tiie smell of sulphur burn- 
ing slowly. It destroys nxMt regetable co- 
lours, but the blues are reddened by it pre- 
yfiooM to their being discharged. A pleasing 
instsncie of its cflfect on colours may be ex- 
hibited by holding a red rose over the blue 
£ame of a common match, by which the co- 
lour will be discharged whercTer the sulphur- 
ous acid comes into cimtact with it, so as to 
it beautifully vari^ated, or entirely 
If it be then dipped into water, the 
sedncss after a time will be restored. 

The specific grsvity of sulphurous acid 
gas, as given by MM. Ihenard and Gay 
LoBsac, is 2.2553, but by Sir H. Davy is 
2.8205, and hence 100 cubic inches weigh 
68 grains; but its spec. gr. roost probably 
dMNild be e^imated at 2.822, and the weight 
of 100 cubic inches will become 67.777. Its 
constituents by volume are^ one of oxygen, 
and one of vapour of sulphur; each having 
m spec. gr. of l.lil, condensed so that both 
volumes occupy only one. Or, in popular 
langui^^ sulphurous arid may be said to 
^ft a solutioo of sulphur in oxygen, which 
doubles the weight oif this gas without aug- 
menting its bulk. It obviously, therefore, 
consists by weight of equal quantities of the 
two constituents. Its equivalent will either 
he 2 oxygen -^ 2 sulphur a= 4.0 ; or 1 oxy- 
gen -f- 1 sulphur := 2. Now the analysis of 
sulphite of baryta by Berselius gives 209.22 
base to 86.53 acid; whiofar bong reduced, 
prese nts for the prime equivalent of sulphur- 
ous add the number 4. Hydrogen and car- 
bon readily decompose sulphurous add at a 
led heat, and even under it. Mr Higgins 
discovered, that liquid sulphurous add dis- 
solves iron, without the evolution of any gas. 
The peroxides of lead and manganese furnish 
oxygen to convert it into sulphuric acid, which 
Ibrms a sulphate with the resulung metallic 
proloxide. 

Sulphurous add is used in bleaching, par- 
ticularly for silks. It likewise discharges ve- 
getable stains and iroo>moulds irom linen. 

In combination with the salifiable bases, it 
Ibnns sulphites, which differ from the sul- 
phates in their properties. The alkaline sul- 
phites, are more soluble than the sulphates, 
the earthy less. They are converted into sul- 
phates by an addition of oxygen, which they 
acquire even by exposure to the air. llie 
ffylphki* of lime u the slowest to undergo 
this change. A strong heat dther expels their 
add entirely, or converts them into sulphates. 
l!liey have all a sharp, disagreeable, sulphur- 
ous taste. The best mode of obtaining them 
is by recdving the sulphurous add gas into 
vrater, holding the base, or its carbonate, 
in solution, or diffused in it in fine powder. 
None of them bas yet been applied to any 
use in the arts. 

By putting sulphuric add and mercury 



into the sealed end of a glass tube recurved^ 
then sealing the other end, and applying heat 
to the former, Mr Faraday obtained a liquid 
sulphurous add.— <P*. Tr. 1823.) M. Bus- 
sy {Ann. de Qdm.for Matf 1624) says, that 
he liquefied the same gas, by tnnsmttting it 
through fused chloride of caldum into a flask 
surrounded with a mixtniie of ice and salt* 
It renuutts in a liquid state in the sir at the 
temperature of 0^ F. It is a colourless, trans^ 
parent, and very volatfle liquid, of a spedfic 
gravity = 1.45. It boils at 14° F. ; but in 
consequence of the cold produced by the eva* 
poration of the portion that flies off, the re^ 
sidue remdns liquid. It causes a feeling of 
intense cold when dropped on the hand. By 
evaporation of the add m vacuo, M. Bussy 
froze alcohol, sp. gr. 0.850. 

M. A. de la Kiv^ while experimenting 
upon the liquefaction of sulphurous add by 
cold, remarked the formation of crystals in 
several cases, which he afterwards found to 
be hydrated sulphurous add, analogous to 
those of hydrate of chlorine. 

ACID (HTPOSULPHUROUS). In 
the 85th volume of the Annales de Chimie, 
M. Gay Lussac describes permanent crystal- 
lizable salts having lime and strontia for 
their base; combined with an acid of sulphur, 
in which the proportion of oxygen is less thatt 
in sulphurous add ; but this add he does not 
seem to have examined in a separate state. 
Those salts were procured by exposing solu- 
tions of the sulphurets of the earths to the 
air, when sulphur and carbonate of lime pre- 
cipiteted. When the filtered liquid is then 
evaporated, and cooled, colourless crystals 
form. The calcareous are prismatic needles^ 
and those with strontia are rhomboidal. He 
called these new compounds sulphuretted euU 
phites. Those of potash and soda he also 
formed by heating their sulphites with sul- 
phur; when a quantity of sulphurous add 
was disengaged, and neutral salts were form- 
ed. M. Gay Lussac farther informs us, that 
boiling a solution of a sulphite with sulphur, 
determines the formation of the sulphuretted 
sulphite, or hyposulphite ; and tliat iron, zim^ 
and manganese, treated with liquid sulphur- 
ous acid, yield sulphuretted sulphites : fhns 
which it follows, that a portion of the sul- 
phurous add is decomposed by the metal, 
and that the resulting oxide combines with 
the other portion of the sulphurous add and 
the liberated sulphur. The hyposulphites are 
more permanent than the sulphites ; they do 
not readily pass by the action of the air into 
the stete of sulphate ; and though decompos- 
able at a high heat, they resist the action of 
fire longer than the sulphites. Tliey are d»* 
imposed in solution by the sulphuric, mu- 
riatic, fluoric, phosphoric, and arsenic adds^ 
sulphurous add. is evolved, sulphur is precis 
pitated, and a new salt is formed. Such is 
the account given of these by M. Gay Lussac, 



ACID 



109 



HYPOSULPHLROU& 



imd copied ioto the second Toluroe of the 
Tnut^ de Chimie of M« Hienardt published 
in 181i. 

No additional information was communi- 
cated to the worid on this subject till January 
1819, when an ingenious paper on the hypo- 
sulphites appeared in the Eidinburgh Fbilo- 
imphical Journal, followed soon by two others 
in the same periodical work, by Mr Hers- 
cheL 

In order to obtain hypoaulphurous acid, 
Ifr Herschel mixed a dilute solution of hy- 
posulphite of strootia with a slight excess 
of dilute sulphuric acid, and after agitation 
poured the mixture on three filtera. The 
first was received into a solution of carbonate 
of potash, from which it expelled carbonic 
acid gas. Tlie second portion being received 
successively into nitrates of silver and mer- 
cury, precipitated the metals copiously in the 
state of sulphureta, but produced no effect on 
solutions of copper, iron, or sine Tlie third, 
lieipg tasted, was add, astringent, and bitter. 
When fresh filtered, it was clear; but it be- 
came milky on standing, depositing sulphur, 
and exhaling sulphurous acid. A moderate 
exposure to air, or a gentle heat, caused its 
entire decomposition. 

The hsbitudes of oxide of silver in union 
with this sdd, are very peculiar. Hyposul- 
phite of soda being poured on newly predpi- 
tated oxide of silver, hyposulphite of silver 
was formed, and caustic soda eliminated; 
the only instance, says Mr Herschel, yet 
known, of the direct displacement of a fixed 
alkali by a metallic oxide, via humidti* On 
the other hand, hyposulpJiurous add newly 
disengaged from the hyposulphite of bsryta 
by dilute sulphuric add, readily dissolved, and 
decomposed muriate of silver, forming a sweet 
solution, from which alcohol separated the 
metal in the state of hyposulphite. << Hius 
the affinity between this add and base^ 
unaitiited by any double decomjwsiUon, is 
such as to form an exception to aJl the ordi- 
nary rules of chemical union.'* Hiis add 
has a remarkable tendency to form double 
sslts with the oxides of silver and alkaline 
bases. The hyposuliriiite of silver and soda 
lias an intensely sweet taste. When hyposuU 
phite of ammonia is poured on muriate of 
silver, it dissolves it ; and if into the saturated 
solution alcohol be poured, a white salt is 
predpitated, which must be fordbly squeexed 
-between blotting paper, and dried in vacuo. 
It is very soluble in vrater. Its sweetness is 
unmixed vrith any other flavour, and so in- 
tense as to cause pain in the throat. One 
grain of the salt communicates a perceptible 
sweetness to 32,000 grains of water. If the 
alcoholic liquid be evaporated, thin lengthen- 
ed hexangular plates are sometimes filmed, 
which are not altered by keeping, and consist 
of the same prindples. 

ILe best way of obtaining the alkaline 



hyposulphites, Is to pass a current of sulphu- 
rous sdd gas through a Itrivwrn, formed bf 
boiling a watery solution of alkali, or alkaUno 
earth, along with sulphur. The whole of the 
sulphurous add is converted into die hypo* 
sulphite, and pure sulphur, unmixed with any 
sulphite, is predpitated, while the hyposuU 
phite remains in solution. 

Mr Herschel, from his experiments on the 
hyposulphite of lime, has deduced the prime 
equivalent of hypoaulphurous add to bo 
59.25. He found that 100 parts of crystals 
lized hyposulphite of lime were equivalent to 
181.77 hyposulphite of lead, and yielded of 
carbonate of lime, by carbonate of ammooiaa 
a quantity equivalent to 21.75 gr. of lime^ 
Hierefore the theory of equivalent ratios gives 
us this rule ;— 

As 21.75 gr. lime are to its prime equiv»« 
lent 3.S, so are 121.77 gr. of hyposulphite of 
lesd to iiM prime equivalent In numben 
21.75 : a5 : : 121.77 : 19.6. From this 
number, if we deduct the prime of the oxide 
of lead ss l^ the remainder 5.6 will be the 
double prime of hyposulphurous sdd. Now 
this number does not differ very ftar from 6« 
Hence we see that the hyposulphites^ for 
thdr neutral condition, require of this feeble 
add 2 prime proportions. One prime pro» 
portion of it is obviously made up of one 
prime of sulphur s: 2, -^ 1 oxygen :^ 1 ( 
and the add equivalent is ss 3. The ays- 
talUxed hjrposuJphite of lime is composed of 
6 sdd -(. a5 lime + 6.75 water, being six 
primes of the last constituent. 

It ought to be ststed, thst when a solution 
of a hyposulphite is boiled down to a certsia 
degree of concentration, it begins to be rapidly 
decomposed, vrith the deposition of sulphur 
and sulphite of lim& To obtain the salt in 
crystals, the solution must be evaporated at h 
temperature not exceeding 140^ Fahr. If it 
be then filtered while hot, it will yield, on 
cooling, large and exceedingly beautiful ci^s- 
tsls, which sssuroe a great variety of compli- 
cated forms. They are soluble in nearly 
their own wdght of water at 37° Fahr. and 
the temperature of the solution fidls to 3 P. 
The spedfic grarity of their saturated sdutton 
at 60^ is 1.300; and when it is 1.114^ the 
liquid contains one-fifth of its wdght Hie 
crystals are permanent in the air. 

Hyposulphites of potash and soda yield de- 
liquescent crystals of a bitter taste, and both 
of them dissolve muriate of silver. Tlie am* 
nioniacal salt is not easily procured in regu- 
lar crystals. Its taste is pungent and disa»> 
greeable. Hie barytic hyposulphite is inso- 
luble; the strontitic is soluble and crystal* 
Usable. like the other hyposulphites, it 
dissolves silver; and while its own taste is 
purely bitter, it produces a sweet compound 
with muriate of silver, which alcohol tlirowa 
down in a syrupy fonn. Hyposulphite of 
magnesia is a bitter tssted, soluble^ crystal- 



ACLD 107 HYPOSULPHUllIC. 

linbkw-nd aonde Hquwccnt laU. All the UBchMiged in air; insdubls in alcohol; 

flame, wluble in 1.58 of boiling water, and in 2&5 r 



iNurn with a lulphumus 

The sweetneaa of liquid bTposulpbite of of water at 60^. 

soda, combined with nmriote of silver, sur- Soda; large quadrangular prisms; bitter; 

paaMB honey in intensity, diffusing itself unchanged in air ; contain 15.54* per cent of 

over die whole mouth and fauces without water; soluble in i.l water at 212^ Fohr. 

any disagreeable or metallic flavour. A coil a^d in 2^ 1 water at 60^. 

of auic wire speedily separates the silver in a Ammonia j difllcultly crystallizabJe; cool 

netaUic state, thus affording a ready analysis taste; unchanged in air; dissolves in less 

of muriate of silver. Muriate of lead is than one of water ; by heat loses water, and 

who aolable in the hyposulphites^ but less is then decomposed ; contains 18.44 per cent 

leadily. of water. 

ACI D (H YPOSULPHURIC). MM. Baryta ; two kinds of crystals ; 10.78 per 

6ay Luflsac and Wellher lurve recendy an- cent water; bitter and astringent; un- 

nounoed the discovery of a new add combi- changed in air ; decrepitates by heat; Mluble 

nation of sulphur and oxygen, intermediate in 1. 1 boiling water, and in 4.04 of water 

between sulphurous and sulphuric acids, to at 64^. 

which they have given the name of hyposul^ StronHa; Urge hexagonal tables; 22.1 

phnric add. It is obtained by passing a per cent of water ; bitter ; unchanged in air ; 

cuncnt of sulphurous add gas over the black not so soluble as the last salt. 

oiide of nuwganeae. A combination takes Lime; in appearance resembles the last; 

place; the excess of the oxide of manganese bitter; 26.24 percent of water; dissolves in 

is aepanted by dissolving the hyposnlpbate of 0l8 boiling water; and in 2.46 of water at 

mM^nmr in water. Caustic baryta preci- 56^ F. 

pitates the manganese, and forms with the Magnesia; hexagonal prisms; unchange- 

new add a vety soluble salt, which, freed able in air; very bitter; fusible; 37.69 per 

from exceas of baryta by a current of car* cent of vrater ; very soluble. 

boooc add, crystallizes regularly, like the Hie metallic oxides all form salts with this 

nitnite or muriate of baryta. Hyposulphate add ; and all the salts, as Gay Lussac has 

of besyta being thus obtained, sulphuric add shown, are soluble in water, and insoluble in 

is cautiously added to the solution, which alcohol. 

throws down the baryta, and leaves the hypo- Hie following table exhibits the rtrnipoai 

snlpbaric add in the water. This add tionofthedifferentaddcompounds of sulphur 

bears considerable concentration under the and oxygen :— 

reedrer of the ur-pump. It consists of five Hyposulphurous add, 20 suL -^ 10 oxygen 

ports of oxfgjBik to four of sulphur. The Sulphurous add, 10 -^ 10 

greater number of the hyposulphates, both Hyposulphuric add, 8-^10 

eanfay and metallic, are sduble^ and crystaU Sulphuric add, 6^ 4- 10 

Use; those of boryta and lime are unalterable Or, if we prefer to consider the quantity of 

in the air. Suberic add and chlorine do not sulphur in each add as s» 2, the oxygen com- 

decompose the baiytic salt. Hie barytic salt bines with it in the following proportions :-.- 

incryrta]soonsistoofbaryta9.75-|-byposul- 1; 2; 2.5; 3. 

Italic add 9.00 -f- water 2.25 s= 20.95. Hyposulphuric add is distinguished by the 

Dr Heeren prepares hyposulphuric add IbUowing properties :— 

nearly as above described ; but he separates lst» It >* decomposed by heat into snlphur- 

the sulphuric add and oxide of manganese in ous and sulphuric acids. 

solution by sulphuret of barium instead of 2d, It forms soluble salts vrith baryt% 

baryta water; because the latter does not strontia, lime^ lead, and silver. 

eonpktdiy remove the oxide of manganese. Sd, The hyposulphates are all soluble^ 

To take away the excess of sulphuret of 4Ah, Hiey yield sulphurous add when their 

bsduniy he passes carbonic add through the solutions are mixed with adds, only if the 

mixture^ applies heat, and flitefs; ami the mixture becomes hot of itself, or be artifidal- 

inid, by due oonoentration, yields pure crys- ly heated. 

lab of hyposulphate of baryta. Bdng de- 5th, Hiey disengage a great deal of sul- 

composed by ndphnric add, the hyposul- phurous add at a high temperature^ and are 

phone add is obtained pure. To obtain the converted into neutral sulphates. 

kigaat quantity of this product, the peroxide Before quitting the adds of sulphur it 

ef manganese should contain no deutoxide^ deserves to be mentioned, that Dr Gules, of 

should be in exceedingly fine powder, and Paris, has, by means of a chest or case caUed 

the whole kept at as low a temperature as Boete Fumigatdre^ applied the vapour of 

possible. Anhydrous liquid sulphurous odd burning sulphur, or sulphurous add gas, 

has no action on the peroxide of manganese, mixed with air, to the surface of the body as. 

Tbe finllowing are the chanctenof some by* an air bath, vrith great advantage in many 

poBulphates. chronic diseases of the skin, the joints, the 

PaUuki fine crystals; anhydrous ; bitter;. glwdf» and the lymphatic system. See Salt.. 



ACID 



106 



TARTARIC 



: ACID (TARTARIC). The casks in 
which some Icinds of wine are kept become 
incrusted with a hard substance, tinged with 
the colouring matter of the wine, and other- 
wise impure, which has long been known by 
the name of argalt or tartar, and distinguish- 
ed into red and white, according to its colour. 
This being purified was termed cream, or 
cry$Uds of tartar. It was afterwards disco- 
vered, that it consisted of a peculiar acid com^ 
bined with potash ; and the supposition that 
it was formed during the fermentation of the 
wine was disproved by Boerhaave^ Neuman, 
and others, who showed that it existed ready 
formed in the juice of the grape. It has like^ 
wise been found in other fruits, particularly 
before they are too ripe; and in the tama- • 
rind, sumac, balm, carduus benedictus, and 
the roots of restharrow, germander, and sage. 
Tlie separation of tartaric add from this aci- 
dulous salt is the first discovery of Scheele 
that is known. He saturated the superfluous 
add, by adding chalk to a solution of the 
supertartrate in boiling water as long as any 
effervescence ensued, and eipelled the add 
from the predpitated tartrate of lime by 
means of the sulphuric Or four parts of- 
tartar may be boiled in twenty or twenty- 
four of water, and one part of sulphuric add 
added gradually. By continuing the boiling, 
the sulphate of potash will fall down. When 
the liquor is reduced one-half, it is to be fil- 
tered ; and if anymore sulphate he deposited 
by continuing the boiling, the filtering must 
be repeated. When no more is thrown 
down, the liquor is to be evaporated to the 
consistence of a syrup; and thus crystals 
of impure tartaric add, equal to half the- 
wdgbt of the tartar employed, will be ob- 
tained. 

Tartaric add may be procured by careful 
evaporation in lai^ crystals, which, when 
insulated, are found to be hexaedral prisms, 
with faces parallel, two and t^o. The four 
angles which are most obtuse are equal' to 
one another, measuring each 129^; the two- 
remaining ones are also equal, and measure 
102^. The prism is terminated by a thiee- 
sided pyramic^ the indinations of whose laces 
aie 102.5, I22f^, and 125<>. The prisms are 
aometimes much compressed in a direction- 
parallel to the axis. This takes place when 
the add has been very slowly crystallised by 
evaporating a solution of it. Its taste is very 
add and agreeable, so that it may supply the 
place of lemon-juice. It is very soluble in 
water. Burnt in an open fire, it leaves a 
coaly residuum ; in close vessels it gives out 
carbonic add and carburetted hydrogen gas. 
By distilling nitric add off the crystals, tfiey 
may be converted into oxalic add, and the 
nitric add passes to the state of nitrous. 

To extract the whole add from tartar, M. 
Thenard recommends, after saturating the re^ > 
dundant add with chalk,, to. add muriate oC 



lime to the lupenutant neutnl tartnte^ by 
which means it is completely deco mp osed. 
The insoluble tartrate of lime being washed 
with abundance of water, is then to be treat- "• 
ed with three-fifths of its wdght of strong . 
sulphuric add, diluted preriously with five 
parts of water. But Fourcroy*s proc e s s , as 
improved by Vauquetin, seems cheaper. Tar- 
tar is treated with quicklime and boiling water 
in the proportion, by the theory of equiva- 
lents, of 100 of tartar to 90 of dry lime, or 
40 of the slaked. A caustic magma is ob- * 
tained, which must be evaporated to dryness, 
and gently heated. On digesting this in' 
water, a solution of caustic potash is obtsined, 
while tartrate of lime remains ; horn which 
the add may be separated by the equivalent • 
quantity of oil of vitriol. 

According to Bendius, tartaric add is a 
compound of 3.807 hydrogen -f- 35.960 car- - 
bon4.6a213 oxygens 100: to wUch to- 
suit he shows that of M. Gay Lussac and 
Tbenard to correspond, when allowance is 
made for a certain portion of water, which • 
they had omitted to estimate. Hie analysis, 
of tartrate of lead gives 8.384> for the add 
prime equivalent; and it may be made up oT 

3 hydrogen =0.375 4^46 

4 carbon sss aOOO 35.82 

5 oxygen as 5.000 59.70 

a375 100.00 
Tlie crystallized add is a compound of 8.375 
add 4- 1.125 waters 9.5; orinlOOpans, 
8a 15 add 4-1 1.85 water. 

The prime equivalent of tartaric add in 
crystals is, by my results, 9.25 ; and it seems 
made up of carbon 4 atoms ss 3 •}- hydrogen ■ 
2 atoms^ 0.25 •}- oxygen 6 =s 6 ; or of car- 
bon 4 atoms, oxygen 4 atoms, and water 2. 
These atoms of water enter into dry tartrate 
of lead ; and hence the crystals of add con- 
tain no water unessential to thdr constitution* 
-^PhU. Trans. 1822. 

M. Rose has shown, that tartaric add haa 
a peculiar influence in several cases of che- 
mical analysis. When a solution of red oxide ■ 
of iron is mixed with tartaric add, the oxide* 
can be precipitated ndther by caustic alkalia< 
nor by thdr carbonates or succinates ; but 
tincture of galls, triple prussiate of potash,, 
and alkaline hydrosidphurets, show the pre. 
sence of iron in such a solution, llie same 
thing is true of the oxides of titanium, man- 
ganese, cerium, yttrium, cobalt, and nick^ 
as well as with alumina and magnesia. So- 
lution of protosulphate of iron with tartaric 
add is merdy rendered intensely green by^ 
ammonia, and changes after long standing in 
the air to a yellow-coloured solution, whicrb. 
contains iron. 

. The oxide of lead likewise is not separable 
by alkalis, when its solution has been treated 
with so much nitric add that no tartrate o^ 
ll?ad can piecqiitate. Oxides of tin. and cop- 



ACID 



id9 



TARTARia 



per fiill under tbe same head. Lastly^ oxid& 
of antimooy, when its solution in an add is 
mized with the tartaric, resists hoth alkalis 
and the moat copious dilution with water. 
Thus, oxide of bismuth may be separated 
from oxide of antimony ; lor the former re- 
, sists the influence of tartaric add. Muriate 
of platinum, the oxides of siWer, zinc, and 
unnium, are not altered by tartaric add.— 
Gilberi*s Jnn. Ixxiii. 74. 

Hie tartrates, in their deoompoeition by 
fire, comport themsetves like all the other 
▼Cj^etable salts, except that those with excess 
of add yield the smell of caromei when heat-' 
od, and afford a certain quantity of the pyro- 
tartaric add. Ail the soluble neutral tar- 
.tnles form, with tartaric add, bitartrates of 
sparing solubility; while all the insoluble 
tartrates may be diasolyed in an excess of 
their add. Hence^ by pouring gradually an 
.excess of add into bsoTta, strontia, and lime 
waters^ the predpitates formed at first cannot 
^fiul to disappear; while those obtained by an 
excess of the same add, added to concen- 
trated solutions of potash, soda, or ammonia, 
and the neutral tartrates of these bases as well 
as* of magnesia and copper, must be perma- 
nent. The first are alwajrs flocculent; the 
second «lways crystalline; that of copper 
alone, is in a greenish-white powder. It 
likewise follows, that the greater number of 
adds ought to disturi> the solutions of the 
alkaline neutral tartrates, because they trans- 
form these salts into bitartrates; and on the 
coDlTary they ought to affect the solution of 
the neutral insoluble tartrates, which indeed 
.always happens, unless the add cannot dis- 
solve the base of the tartrate. Tlie order of 
.apparent affinities of tartaric add are, lime, 
baryta, strontia, potash, soda, ammonia, and 



. iartar, because much more so than the super- 
tartrate, crystallizes. in oblong squares, bevel- 
led at the extremities. It has a bitterish 
taste^ and is decomposed by heat, as its solu- 
tion is even by standing some time. It is 
used as a mild puigative. 

Tbe supertartrate of potash, already men- 
tioned at the beginning of this artide, is 
much used as a cooling and gently opening 
medicine, as well as in several chemical and 
pharmaceutical preparations. Mixed with an 
equal wdgbt of nitre, and projected into a 
red-hot cnidble, it detonates, and forms the 
whiu Jlux: treated in the same way with 
half its wdght of nitre, it forms the black 
Jluxi and simply mixed with nitre in various 
. proportions, it is called rtmfius. It is like- 
wise used in dydng, in hat-making, in gil4- 
ing, aud in other arts. 

The blanching of the crude tartar is aided 
by boiling its solution with l-20th of (npe 
clay. 

According to the analysis of BerzeUus, it 
consists of 70.45 acid -f 24.8 potash .^ 4.75 
water := 100; or 

2 primes add, as 16.75 70.30 
I potash, s= 5.95 24.95 

1 water, = 1.125 4.75 



Hie tartrates of potash, soda, and ammo- 
nia, are not only susceptible of combining to- 
gether, but abo with the other tartrates, so as 
to form double or triple salts. We may thus 
easily conceive why the tartrates of potash, 
soda, and ammonia, do not disturb the so- 
lutions of iron and manganese; and on the 
other band, disturb the solutions of the salts of 
baryta, strontia, lime, and lead. In the first 
case^ double salts are fonned, howevor smaU 
a quantity of tartrate shall have been em- 
ployed; in the second, no double salt is 
fionned, unless the tartrate be added in very 



The tartrates of lime and baryta are white, 
pulverulent^ and insoluble. 

Tartrate of strontia, formed by the double 
decomposition of muriate of strontia and 
tartrate of potash, according to Vauquelin, is 
aolnble, crystallizable, and oonsbts of 52.88 
Btronti* and 47.12 add. 

That of magnesia forms a gelatinoua or 
'gummy mass. 

Tartrate of potash, formerly called tolubU 



23.825 100.00 
60 parts of water dissolve 4 of bitartrate at a 
boiliog heat, and only 1 at 60^ Fahr. It is 
quite insoluble in alcc^oL It becomes very 
soluble in water, by adding to it one-fifth oi 
its weight of borax, or even by the addition 
of boradc add. It appears by Berzelius, that 
neutral tartrate of potash, dried in the son, 
differs from the bitartrate, in containing no 
water of crystallization. He states it to be a 
compound of 58.69 add-^- 41.31 potash = 
100; which afford 155.7 tartrate of lead. 
Now, a375: 5.95:: 58.5: 41.5, which are 
the equivalent proportions. 

On considering the great solvent property 
of cream of tartar, and that it is even capable 
of dissolving various oxides which are inso- 
luble in tartaric add, as the protoxide of an- 
timony, M. Gay Lussac has recommended it 
as a useful agent in diemical analysis. He 
thinks that in many cases it acts the part of 
a single add. According to this riew, tartar 
emetic would be a compound of the creatn 
tartar add and protoxide of antimony. 
Cream of tartar generally contains from 3 to 
5 per cent of tartrate of lime^ which are in a 
great measure separated when 3 parts of tar- 
tar are boiled with 1 of borax for a few mi- 
nutes in a sufficient quantity of water. Tbe 
soluble cream of tartar which is obtained by 
this process is deliquescent ; it dissolves in its 
own weight of boiling water at 54.5S and 
in half its weight of bdjing water. Its solu- 
tion is very imperfectly decomposed by the 
sulphuric, nitric, and muriatic adds. 4 parts 
of tartar and 1 of boradc add form a pennfu 



ACID 110 TUNGSfie. 

ncnt aaline compound, very soluble in lira- ecJolired gvejr bj the sulplnir, wiH renlwi. 

tor. Alum alao increaaes tlie sdubiltty of It is to be washed, and heated red hot, to 

tartar. driTe off the sulphur. 

Bj saturating the superfluous acid in this One operation is not sufficient to free the 

> supertartrate with soda, a triple salt is form- titanic acid perfectly from iron ; the product 

ed, which crystallises in larger regular prisms is therefore again to be heated in a tube, 

of eight nearly equal sides, of a bitter taste, through which sulphuretted hydrogen Is 

- efflorescent, and soluble in about five parts of 'passing, and then treated as before; when 

water. It consists, according to Vauquelin, of again washed and heated red hot^ it becomes 

54 parts tartrate of potash and 46 tartrate of perfectly white and pur& 

soda ; and was once in much repute as a pur- Tbe operation may be shortened by heat- 

gatiTe by the name of Moehette SaU or Sel de ing the titaniferous iron with sulphur in a 

Seignette* crucible, and then acting by concentrated 

The tartrate of soda is much less soluble muriatic acid : biit in this iint operation, as 

than this triple salt, and crystaUiases in slen- much iron remains with the titanic add as 

der needles or thin plates. exists in rutilite ; then an operation with sul- 

The tartrate of ammonia is a Tery soluble phuretted hydrogen renders the substance 

bitter salt, and crystallises easUy. Its solu- perfectly pure. 

tion is spontaneously decomposable. It is said to consist of titanium, 66.05 

This too forms, with tartrate of potash, a oxygen, S3.95; 

triple salt, the solution of which yields, by whence^ if, like the other metallic adds, this 

cooling, fine pyramidal or prismatic efflores- be supposed to contain 3 atoms of oxygen* 

• cent crystals. Though both the neutral salts the atomic weight of the metal will be 5.83^ 

'that compose it are bitter, this is not, but has or possibly 6l 

a cooling taste. See Salt. Add titanate of potash consists of 

M. Fabroni says, that sulphuric acid being titanic add, - 62.33 7 ^^^ 

mixed with three parts of boiling water, and potash, - - 17.77 ) 

cream of tartar in excess, gives a fluid which, Arid titanate of soda of 

after bdng evaporated, cooled, and allowed titanic acid, - 83.15) |^ 

to deposit undecomposed tartar, sulphate of soda, - - 16.85 y 

potash, &c. will not furnish any odier de- Sulphotitanic add consists of 

posit, and resembles oil in its appearance. titanic add, - 76.67 ^ 

When further evaporated to the consistence sulphuric add» - 7.67 > 100. 

of syrup, and again cooled, it solidifies in a water, - - 15.66 ) 

mass composed of imperfect prismatic crys- Oxalo-titanic add, of titanic add 74. 1 , 

-stals, which when dry have something the oxalic add 10.4, water 15.5.. 

appearance of camphor. It dissolves rapidly Sulphuret of titanium consists of titaniuni 

4n water, but in alcohol yields its tartaric 49. 17, sulphur 50.83. 

•add, while acid sulphate of potash is left. Protochloride of titanium consists of tit»- 

On analysis it gave 72 tartaric add, and 28 nium 6, chlorine 3.6. 

sulphate of potash. Gf or. de Fitiea, vi. 452. Perchloride of titanium consists of titani- 

ACID (TITANIC). By i\ising powder- um 6.66, chlorine 7.94. 
ed rutilite with thrice its wdght of carbonate Annales de Chinu xxiii. 353. AnnaU of 
of potash, dissolving the compound in mu- Phil. N. S. ix. 18. 
riatic add, predpitating by caustic ammonia, ACID (TUNGSTIC) has been found 
digesting the predpitate for a certain time only in two minerals ; one of which, formep. 
with hydrosulphuret of ammonia, and then ly called tungsten, is a tungstate of lime, 
digesting the solid matter left in weak mu- and is very rare ; the other, more common, 
riatic add, M. Rose obteins a perfectly white is composed of tungstic acid, oxide of iron^ 
oxide of titanium, which is not attacked by and a little oxide of manganese. The acid 
adds, but which becomes red by touching is separated from the latter in the following 
moistened litmus. As it acts with alkalis way. Hie wolfram cleared fW>m its siliceous 
precisely as an add, M. Rose calls it titanic gon^ve, and pulverised, is heated in a mat- 
add, rass with five or ax times its wdght of mo- 
He has more recently given the following riatic add, for half an hour. The oxides of 
process for obtaining titanic add. Pulverise iron and manganese bdng thus dissolved, 
and wash menachanite, heat it highly in a we obtain the tungstic add under the form 
porcelain tube, and pass dry sulphuretted of a ydlow powder. After washing it re- 
hydrogen gas over it ; the oxide of iron will peatedly with water, it is then digested in an 
become sulphuret, the titanic add will re- excess of liquid ammonia heated, which disi. 
main unchanged. When cold, digest the solves it completely. The liquor is filtered 
product in strong muriatic acid ; sulphuret- and evaporated to dr3mess in a capsule, 
ted hydrogen will be cooled, and the titanic The dry residue bdng ignited, the ammonia 
add, rendered insoluble by the heat, and flies off, and pure tungstic acid remains. If 



ACO 111 ACT 

tte'wbofeof tbewoUWun has not been de- os. dr, gri 

eompoacd in this iipention» it must be sub- Water and Tidatile matter^ 16 6 

jected to the muriatic acid again. Fibrous matter, - 13 

It is tasteless, and does not affect vegetable Green resin, - - 0- 1 50 

' coloon. The tongstatcs of the alkaUs and Vegetable albuipen (Pflannenei- 

BH^csia are soluble and crystalltsable ; the weiu), - - - 3 55 

other earthy ones are insoluble, as well as Extractive, with various acetates 

llioae of the metallic OKides. Theadducom- and muriates, - - 4 50 

posed of 100 parts metallic tungsten, and Gummy matter, - - 6 

25 or 26.4 oxygen. Malate and citrate of lime^ 1 56 

ACID (TUN6STOUS). What has been 

Hms called appears to be an oxide of tung- 20 2 30 

The distilled water of aconite, though 



ACID (URIC). Hie same with LrrBK smelling rank of the plant, is not poisonous. 

AoD; which see^ The noxious principle is therefore not vol». 

ACID (VEGETaSULPHURIC). tile. The details of the analysis have not 

Tbia compound was obtained by M. Bra- reached this country. 



coonol, in treating ligneous fibre with sul- ACROSPIRE. Tbeplumula is that part 

phuric acid. It consists of sulphur, caH)on, of the embryon of a plant destined to b^ 

hydrogen, and oxygen, or of a vegetable come the stem, and which bears the cotyfi- 

matter and the elements of sulphuric add, dons. According to Grew, the acrospire is 

but in propor ti on s unknown. the piumula of barley developed by germina-. 

ACID (XANTHIC). See Acid (Hy- tion. It is lometimeB named /ilan/Wo. 

DBOXAMTBic). ACTINOLITE. ^aA/sl«m of Werner. 

ACID (ZOONIC). In the liquid pro- JmpMbole JctinoiehegahlreofUany. There 

cored by dfistillation fi'om animal substances are three varieties of this mineral ; tiie crys* 

which had been supposed to contain only talluedi the atbettout, and the glasty. 

CBibooate of ammonia and an oil, BerthoUet Isl, Crystallired actinolite. Colour tsei:- 

imagined he had discovered a peculiar add, green, and green of darker shades. It crys^ 

to which he gave the name of toonic Hie- tallixes in long oblique hexaedral prisms, 

nard, however, has demonstrated, that it is with irregular terminations. Crystds fire- 

merely acetic acid combined with animal quentky striated lengthwise, sometimes adcu^ 

lar. Its lustre is signing. It is translucent. 



ACIDIFIABLE. Capable of bdng Occasionally it is found in silky fibres. Its 

converted into an add by an addifying prin- sp. gr. varies from 3.0 to 3.3i Fracture 

ciple. (See Acii>.) Substances possessing usually radiated; sometimes it is foliated 

property are called ranUcait or addifiabk with an indistinct twofold deavage. It 



scratches glass. 

ACIDIFYING PRINCIPLE. Seere^ 2rf, Asbestous actinolite. Colours gi«ei^ 
marks on this subject, in the general article Terging on grey and brown, and smalt-blue. 



Massive^ and in elastic capillary crystals, 
ACIDIMETRT. The measurement of which are grouped in wedge-shaped, radiated, 
the strength of adds. His is effected by or promiscuous masses. Internal lustre pear- 
saturating a given wdgfat of them with an ly. Melts before the blowpipe into a dark 
alkaline base ; the quantity of which requi- glass. Fracture intermediate between fibrous 
site Ibr the purpose is the measure of their and narrow radiated. FVagments wedged 
power. shaped. Opaque. Soft. Tough but sec- 

ACIDULEk A term applied by the tile. Sp. gr. 2.7 to 29. 
French chemists to those salts in which the 3dy Glas^ actinolite. Colours, mountain- 

base ia combined with such an excess of green, and emerald-green. In thin six-sided 

add, that they manifestly exhibit add pro- needle-form crystals. Has cross rents. Sp. 

pcrties; such ss the supertartrete of potash, gr. from 3.0 to 3.2. The composition of 

ACONITA. A poisonous vegetable prin- actinolite is very diff*erent]y stated by diffe- 

dple^ probably alkatine, supposed to exist in rent analysts. Laugier*s results with glassy 

-the aconkwn napellutt or wolfsbane. In actinolite are the following, and they approxi- 

-aome British journals it is stated that M. mate to those of Vauquelin on asbestous ac- 

Brandea had procured this alkaline prindple. tinolite ; silica 50, lime 9. 75, magnesia 19.25^ 

Bat I observe in his translation of my Die- oxide of iron 1 1, alumina 0.75, oxide of man- 

•tioaary into the German language, that he ganese 0.5, oxide of chromium 3^ potash 0.5» 

refers the point to the researches of M. Pes- moisture 5, loss 0.25. 28.2 of alumina and 

chier of Geneva, who has not hitherto made 3.S4 of tungstic add were found in 100 parti 

it distinctly out. Buchols analysed the herb of asbestous actinolite from Cornwall, 
aconite, and found the folkming constituents Actinolite is found chiefly in primitive dts- 

in 20 onnccB :— tricts with a magnesian basis. It acoompa^ 

■ nies talc, and some micaceous rocks. Its 



ADI 



112 



ADI 



piioci{»l localities are Zillerthal in the Xy- 
lol, Mont St Gothard, near Soltsburg in 
Saxony, in Norway, and in Piedmont. In 
Great Britain, it is found in Cornwall and 
Wales ; and in Glen Elg, the isles of Lewis 
^d Sky. It is never found in secondary 
mountains. 

ADAMANT. See Diamond. 

ADHESION. See Cohesion. 

ADHESIVE SLATE. See Slate. 

ADJPOCERE. The attention of che- 
mists has been much excited by the sponta- 
neous conversion of animal matter into a sub- 
stance considerably resembling spermacetL 
The fact has long been well known, and is said 
to have been mentioned in the works of Lord 
Bacon, though I have not seen the passage. 
On the occasion of the removal of a very 
great number of human bodies from the an- 
cient burying-place Des Innocens at Paris, 
/acts of this nature were observed in the 
most striking manner. Fourcroy may be 
called the scientific discoverer of tliis pecu- 
liar matter, as well as the saponaceous ammo- 
iiiacal substance contained in bodies aban- 
doned to spontaneous destruction in large 
masses. This chemist read a memoir on the 
subject in the year 1789 to the Royal Aca- 
demy of Sciences, from which I shall ab- 
stract the general contents. 

At the time of clearing the before men- 
tioned burying-place, certain philosophers 
were specially charged to direct the precau- 
tions requisite for securing the health of the 
.workmen. A new and singular object of 
research presented itself, which had been ne- 
cessarily unknown to preceding chemists. 
It was impossible to foretell what might be 
the contents of a soil overloaded for succes- 
sive ages with bodies resigned to the putre- 
iSEu:tive process. This spot differed from 
common burying-grounds, where each indi- 
vidual object is surrounded by a portion of 
the soiL It was the burying-ground of a 
large district, wherdn successive generations 
of the inhabitants had been deposited for up- 
wards of tliree centuries. It could not be 
foreseen that the entire decomposition might 
be retarded for more than forty years ; nd- 
ther was there any reason to suspect that any 
remarkable difference would arise from the 
angularity of situation. 

The remains of the human bodies im- 
mersed in this mass of putrescence were 
found in three different states, according to 
the time they had been buried, the place they 
occupied, and their relative situations with 
regard to each otliet*. "Die most ancient 
were simply portions of bones, irregularly 
dispersed in the soil, which had been fre- 
quently disturbed. A second state, in cer- 
tain bodies which had always been insulated, 
exhibited the skin, the muscles, tendons, and 
aponeuroses, dry, brittle, hard, more or less 
grey, and similar to what are called mum- 



mies iff certain caverns where this change 
has been observed, as in the catacombs at 
Home, and the vault of the Cordeliers at 
Tholouse. 

The third and most singular state of theae 
soft parts was observed in the bodies which 
filled the common graves or repositories. By 
this appellation are understood cavities oif 
thirty feet in depth, and twenty on each side, 
which were dug in the burying-ground of 
the Innocents, and were appropriated to con- 
tain the bo^es of the poor; which wene 
placed in very dose rows, each in its pro- 
per wooden bier. The necessity for dispos- 
ing a great number, obliged the men chaiged 
with this employment to arrange them so 
near each other, that these cavities might be 
considered when filled as an entire mass of 
human bodies separated only by two planka 
of about half an inch thick. Each cavity 
contained between one thousand and fifteen 
hundred. When one commcm grave of tfaia 
magnitude was filled, a covering of about 
one foot deep of earth was laid upon it, and 
another excavation of the same sort was 
made at some distance. Each grave re- 
mained open about three years, which was 
the time required to fill it According to 
the urgency of circumstances, the graves 
were again made on the same spot after an 
interval of time, not less than fifteen yean^ 
nor more than thirty. Experience had taught 
the workmen, that this time was not snfll- 
cient for the entire destruction of the bodies, 
and had shown them the pn^essive changea 
which form the object of M. Fourcroy *s me- 
moir. 

The first of these larg^ graves opened in 
the presence of this chemist, had been closed 
for fifteen years. The coffins were in good 
preservation, but a little settled, and the wood 
(I suppose deal) had a yellow tinge. When 
the covers of several were taken ofi^ the bodiea 
were observed at the bottom, leaving a con- 
siderable distance between their surface and 
the cover, and flattened as if they had suflfered 
a strong compression. The linen which had 
covered them was slightly adherent to the 
bodies ; and, with the form of the different 
regions, exhibited, on removing the linen, 
nothing but irregular masses of a soft ductile 
matter of a grey-white colour. Tliese masses 
environed the bones on aU sides, which had no 
solidity, but broke by any sudden pressurew 
The appearance of this matter, its obvious 
composition and its softness, resonbled com- 
mon white cheese ; and the resemblance was 
more striking from the print which the threads 
of the linen had made upon its surface. This 
white substance yielded to the touch, and be- 
came soft when rubbed for a time between 
the fingers. 

No very offensive smell was emitted ftvan 
these bodies. The novelty and singularity of 
the spectacle, and the example of the grave- 



ADI 



113 



ADI 



^Bggcn» dispelled ereiy idea either of disgust 
or apprehenflioD. These, men asserted that 
thej never found this matter, bj them called 
gnu {fat), in bodies inteired alone ; but that 
the accumulated bodies of the common graves 
only were sulgect to this change^ On a very 
attentive examination of a number of bodies 
psssad to this state, M. Fourcroy remarked 
that the conversion appeared in different stages 
of advancement, so that, in various bodies, the 
fibrous texture and colour, more or less red, 
were discernible within the fatty matter ; that 
the masses covering the bones were entirely of 
the same nature^ offering indistinctly in all 
the rqpons a grey substance, for the most 
pert soft and ductile, sometimes dry, always 
essy to be separated in porous fragments, pe- 
netrated with cavities, uid no longer exhibit- 
ing any traces of membranes, muscles, ten- 
dons, vessds, or nerves. On the first in^>ec- 
tion of these white masses, it might have 
been concluded that they were simply the 
cellular tissue, the compsrtmeots and vesicles 
of which they very well represented. 

By examining this substance in the difle^ 
lent regions of the body, it was found that 
the skin is particularly disposed to this re- 
markahle alterstion. It was afterwards per- 
ceived that the ligaments and tendons no long- 
er existed, or at least had lost their tenacity ; 
so that the bones were entirely unsupported, 
and left to the action of their own weight : 
whence their rdative places were preserved 
in a certain degree by mere juxtaposition ; 
the least effi>rt being sufildent to separate 
them. The grave-diggers availed themselves 
of this circumstance in the removal of the 
bodies ; for they tolled them up finom heed 
to loot, and by that means separated from 
emch other the extremities of the bones, which 
had formerly been articuUted. In all those 
bodies which were changed into the fatty mat- 
ler, the abdominal cavity had disappeared. 
The teguments and muscles of this region 
being converted into the white matter, like 
the other soft parts, had subsided upon the 
vertdnral column, and were so flattened as to 
leave no place for the viscera ; and according- 
ly there was scarcely ever any trace observed 
in tiie almost obliterated cavity. This ob- 
servatioa was for a long time matter of asto- 
nishment to the investigators. In vain did 
they sedL, in the greater number of bodies, 
the place and substance of the stomach, the 
intestines, the bladder, and even the liver, the 
spleen, the kidneys, and the matrix in females. 
All these viscera were confounded together, 
and for the most psrt no traces of them were 
left. Sometimes only certain irregular masses 
were found, of the same nature as the white 
matter, of different bulks, from that of a nut 
to two or three inches in diameter, in the re- 
gions of tlie liver or of tbe spleen. 

The thorax likewise offered an assemblage 
ef facts no less singular and interesting. The 



external part of this cavity was flattened add 
compressed like the rest of the organs ; the 
ribs, spontaneously luxated in their articula- 
tions with the vertebrae, were settled upon the 
dorsal column ; their arched part left only a 
small space on each side between them and 
the vertebrae. The pleura, the mediastines, 
the lai^ vessels, the aspera arteria, and even 
the lungs and the heart, were no longer dia^ 
tinguishable ; but for the most psrt bad en- 
tirely disappeared, and in their place nothing 
was seen but some parcels of the fatty sub- 
stance. In this case, the matter which was 
the product of decomposition of the viscera, 
chai^lped with blood and various humours, 
differs fVom that of the surface of the body, 
and tbe long bones, in tbe red or brown 
colour possessed by die former. Sometimes 
the observers found in the thorax a mass ir- 
regularly rounded, of the same nature as the 
latter, which appeared to them to have arisen 
from the fat and fibrous substance of the 
heart. They supposed that this mass, not 
constantly fbund in all the subjects, owed its 
existence to a superabundance of fat in this 
viscus, where it was found. For the general 
observation presented itself, that, in similar 
circumstances, the fat parts undergo this 
conversion more evidently than the others, and 
afford a larger quantity of the white matter. 

Tbe external region in females exhibited 
the glandular and adipose mass of tbe breasts 
converted into the fatty matter, very white 
and homogeneous. 

The head was, as has already been r^ 
marked, environed with the fatty matter; 
the face was no longer distinguishable in the 
greatest number of subjects ; the mouth, dis- 
organized, exhibited neither tongue nor pa- 
late ; and the jaws, luxated and more or less 
displaced, were environed with irregular layers 
of the white matter. Some pieces of the same 
matter usually occupied the place of tbe parts 
situated in the mouth : the cartilages of the 
nose participated in the general alteration of 
tbe sldn ; the orbits, instead of eyes, contained 
white masses ; the ears were equally disor- 
ganized ; and the hairy scalp, having under- 
gone a similar alteration to that of tibe other 
organs, still retained the hair. M. Fourcroy 
remarks incidentally, that the hair appears to 
resist every alteration much longer than any 
other part of the body. The cranium con- 
stantly contained the brain contracted in bulk ; 
blackuh at the surface^ and absolutely changed 
like the other organs. In a great number of 
subjects which were examined, this viscus was 
never found wanting, and it was always in the 
above-mentioned state; which proves that the 
substance of the brain is greatly disposed to 
be converted into the fot matter. 

Such was tbe state of the bodies fbund in 
the burial-ground Des Innocens. Its modi- 
fications were ako various. Its consistence 
in bodies lately changed, that is to say, from 

H 



ADI IH A^I 

three to five yean, yna soft and very ductile, ment socm conYinoed him and M. F. that H 
containing a great quantity of water. In was very fiur from being in the state of an 
other subjects converted into this matter for a earth. It melted by heat, and exhaled in the 
long time, such as those which occupied the form of vapour, which had the smell of a very 
cavities which had been closed thirty or forty fetid fat : spirit of wine separated a concres- 
years, this matter b drier, more brittle, and able oil, which appeared to possess all the 
in denser flakes. In several which were de- properties of spermacetL Each of the three 
posited in dry earth, various portions of the alkalis converted it into soap ; and, in a word, 
fiitty matter had become semitransparent. The it exhibited all the properties of the fatty 
aspect, the granulated texture, and brittleneas matter in the burial-ground of the Innocents 
of this dried matter, bore a considerable re- exposed for several months to the air. Here 
semblance to wax. then was a glandular organ, which in the 

The period of the formation of this sub- midst of the atmosphere had undergone a 
stance had likewise an influence on its pro- change similar to that of the bodies in the 
perties. In general, all that had been form- burying-place ; and this tact sufficiently 
ed for a long time was white, uniform, and shows, that an animal substance, which is 
contained no foreign substance, or fibrous re^ very far from being of the nature of grease, 
mains ; such, in particular, was that afforded may be totally converted into this fatty sub- 
by the skin of the extremities. On the con- stance. 

trary, in bodies recently changed, the fiitty Among the modifications of this remark- 
matter was neither so uniform nor so pure as able substance in the burying-ground before 
in the former ; but it was still found to con- mentioned, it was observed that the dry, 
tain portions of muscles, tendons, and liga- friable, and brittie matter, was most com- 
ments, tiie texture of which, though already monly found near the surface of the earth, 
altered and changed in its colour, was still and the soft ductile matter at a greater depth, 
distinguishable. Accordingly, as the conver- M. Fourcroy remarks, that this dry matter did 
sion was more or less advanced, tliese fibrous not differ from tlie other merely in containing 
remains were more or less penetrated with the less water, but likewise by the volatilisation 
fatty matter, interposed as it were between the of one of its principles, 
interstices of the fibres. This observation The grave-diggers assert, that near three 
shows, that it is not merely the fat which is years are required to convert a body into this 
thus Changed, as was natural enough to think fatty substance. But Dr Gibbes of Oxford 
at first sight. Other facts confirm this asser- found, that lean beef secured in a mnning 
tion. The skin, as has been remarked, be- stream was converted into this fatty matter at 
comes easily converted into very pure white the end of a month. He judges from fkcts, 
matter, as does likewise the brain, neither of that running water is most favourable to this 
which has been considered by anatomists to be process. He took three lean pieces of mut- 
fat It is true, nevertheless, tiiat the unc- ton, and poured on each a quantity of the 
tuous parts, and bodies chai^ged with fat, three common mineral acids. At the end of 
appear more easily and speedily to pass to the three days, each was much changed :— 4hat in 
state under consideration. Tliis was seen in the nitric add was very sof^ and converted 
the marrow which occupied the cavities of the into the fatty matter ; that in the muriatic 
longer bones. And again, it is not to be sup- . add was not in that time so much altered ; 
posed but that the greater part of these bodies the sulphuric add had turned the other black, 
had been emaciated by the illness which ter- M. Lavoisier thinks that this process may 
minated dieir lives ; notwithstanding which, hereafter prove of great use in society. It 
they were all absolutely turned into this fatty is not easy to point out what animsJ sub- 
substance, stance, or what situation, might be the best 
An experiment made by M. PoiAletier de adapted for an undertaking of this kind. M. 
la Salle, and Fourcroy likewise, evinced that L. points out fecal matters ; but I have not 
a conversion does not take place in the fat heard of any conversion having taken place 
alone. M. Poulletier had suspended in his in these animal remains, similar to that of the 
laboratory a small piece of the human liver, foregoing. 

to observe what would arise to it by the con- The result of M. Fourcroy*s inquiries into 
tact of the air. It partly putrefied, without, the ordinary changes of bodies recentiy de- 
however, emitting any very noisome smelL posited in the earUi, was not very extensive. 
Larvte of the dermestes and bruchus attacked The grave-diggers informed him, that those 
and penetrated it in various directions: at last bodies interred do not perceptibly change 
it became dry, and afler more than ten years' colour for the first seven or eight days; that 
suspension, it was converted into a white the putrid process disengages elastic fluid, 
friable substance resembling dried agaric, which inflates the abdomen, and at length 
which might have been taken for an earthy bursts it ; that this event instantly causes 
substance. In this state it had no perceptible vertigo, faintness and nausea, in such persons 
smelL M. Poulletier was desirous of know- ' as unfortunately are within a certain distance 
ing the state of this animal matter, and experi- of the scene where it takes place ; but that 



ADI 



115 



ADI 



when the object of its actum is nearer, a sud- 
den privation of senae^ and frequently death, 
is the consequence. These men are taught 
by experience, that no immediate danger is to 
be fiwred from the disgusting business they 
are engaged in, excepting at this period, which 
they regud with the utmost terror. Tliey re- 
sisted every inducement and persuasion which 
these philosophers nuule use of, to prevail on 
them to assist their researches into the nature 
of this active and pernicious vapour. M. 
Fourcroy takes occasaon from these facts, as 
well as from the pallid and unwholesome 
appearance of the gtave-diggers, to reprobate 
burials in great towns or their ricinity. 

Such bodies as are interred alone, in the 
midst of a great quantity of humid earth, are 
totally destroyed by passing through tlie suc- 
cessive d^^rees of the ordinary putrefaction ; 
and this destruction is more speedy, the 
warmer the temperature. But if these in- 
sulated bodies be dry and emaciated ; if the 
place of deposition be likewise dry, and the 
locality and other circumstances such, that 
the earth, so far from receiving moisture from 
the atmosphere, becomes still more effectually 
parched by the solar rajrs,— 4lie animal juices 
are volatilised and absorbed, the solids con- 
tract and harden, and a peculiar species of 
mummy is produced. But every circum- 
stance is very different in the common bury- 
ing-grounds. Heaped together almost in 
contact, the influence of external bodies af- 
fects them scarcely at all, and they become 
abandoned to a peculiar disorganisation, 
whidi destroys their texture, and produces 
the new and most permanent state of comln- 
naUon here described. From various obsei^ 
vadons, which 1 do not here extract, it was 
found, that this fatty matter was capable of 
enduring in these burying-places for thirty 
or forty years, and is at length corroded and 
carried off by the aqueous putrid humidity 
which there abounds. 

Among other interesting facts afforded by 
the chemical examination of this substance^ 
are the following fnmi experiments by M. 
Fourcroy. 

1. This substance is fused at a less degree 
of heat than that of boiling water, and may 
be purified by pressure tlirough a cloth, which 
disengages a portion of fibrous and bony mat- 
ter. 2. The process of destructive distillation 
by a very grsduated heat was b^pm, but not 
oompleied on account of its tediousness, and 
the little promise of advantage it afforded. 
The products which came over were water 
charged with volatile alkali, a fat oil, concrete 
volatile alkali, and no elastic fluid during the 
time the operation was continued. 3. Frag- 
ments of the fatty matter exposed to the air 
during the hot and dry summer of 1786, be- 
came dry, brittle, and almost pulverulent «t 
the surface. On a careful examination, cer- 
tain portioos were observed to be semitrans- 



parent, and more brittle than the rest These 
possessed all the apparent p ro p erties of wax, 
and did not afi'ord volatUe alkali by dislilhi- 
tion. 4. With water this fatty matter exhi- 
bited all the appearances of soap, and afford- 
ed a strong lather. The dried substance did 
not form the saponaceous combination with 
the same facility or perfection as that which 
was recent About two-thirds of this dried 
matter separated from the water by cooling, 
and proved to l)e the semitransparent sub- 
stance resembling wax. This was taken 
from the surface of the soapy liquor, which 
being then passed through th^ filter, left a 
white soft shining matter, which was fusible 
and combustible. 5. Attempts were made 
to ascertain the quantity of voktile alkali in 
this substance, by the application of lime, 
and of the fix«l alkalis, but without success; 
for it was difficult to collect and appreciate 
the first portions which escaped, and likewise 
to disengage the last portions. The caustic 
volatile alkali, with the assistance of a gentle 
heat, dissolved the fatty matter, and the solu- 
tion became perfectly clear and transparent 
at the boiling temperature of the mixture, 
which was 185° F. 6. Sulphuric add, of 
the specific gravity of 2.0, was poured upon 
six times its weight of the fatty matter, and 
mixed by agitation. Heat was produced, and 
a gas or e£9uvium of the most insupportable 
putrescence was emitted, which infected the 
air of an extensive laboratory for several days. 
M. Fourcroy says, that the smell cannot be 
described, but that it is one of the most horrid 
and repulsive that can be imagined. It did 
not, however, produce any indisposition either 
in himself or his assistants. By dilution with 
water, and the ordinary processes of evapora- 
tion and cooling, properly repeated, the sul- 
phates of ammonia and of lime were <rf)tain- 
ed. A substance was separated from the 
liquor, which appeared to be the waxy mat- 
ter, somewhat altered by the action of the 
add. ' 7. The nitrous and muriatic adds 
were also applied, and afforded phenomena 
worthy of remark, but which for the sake of 
conciseness are here omitted. 8. Alcohol 
does not act on this matter at the ordinary 
temperature of the air. But by boiling it 
dissolves one-third of its own weight, which 
is almost totally separable by cooling as low 
as 55°, The alcohol, after this process, 
affords by evaporation a portion of that waxy 
nuUter which is separable by acids, and is 
therefore the only portion soluble in cold al- 
cohol. Hie quantity of fatty matter operated 
on was 4 ounces, or 2304 grains, of which 
the boiling spirit took up the whole except 
26 grains, which proved to be a mixture of 
20 grains of ammoniacal soap, and 6 or 8 
grains of the phosphates of soda and lime. 
From this experiment, which was three times 
repeated with similar results, it appears that 
alcohol is well suited to afford an analysia of 



ADI 116 . ADI 

the fatty matter. It does not dissolve the are subject. In the modern chemistiT^ soft 
neutral salts ; when cold, it dissolves that animal matters are considered as a composi- 
portlon of concrete animal oil from iirhich tion of the oxides of hydrogen and carbonated 
the volatile alksli hsd flown off; and when asote, more complicated than those of vege- 
heated, it dissolves the whole of the truly table matters, and therefore more incessantly 
saponaceous matter, which u afterwards com- tending to alteration. If then the carbon be 
pletely separated by cooling. And accord- conceived to unite with the oxygen, either of 
ingly it was found, that a thin plate of the the water which is present, or of the other 
fiitty matter, which had lost nearly the whole animal matters, and thus escape in large 
of its volatile alkali by exposure to the air quantities in the form of catbonic acid gas, 
for three years, was almost totally dissolved we shall perceive the reason why this con- 
by the cold alcohol. version is attended with so great a loss of 

The concrete oily or waxy substance ob- weight, namely, about nine-tenths of the 

tained in these experiments constitutes the whole. The azote, a principle so abundant 

leading object of research, as being the pecu- in animal matters, will form ammonia by 

liar substance with which the other well combining with the hydrogen ; part of this 

known matters are combined. It separates will escape in the vaporous form, and the rest 

spontaneously by the action of the air, as well will remain fixed in the fatty matter. The 

as by that of acids. Tliese last separate it in residue of the animal matters, deprived of a 

a state of greater purity, the less disposed the great part of their carbon, of their oxygen, 

acid may be to operate in the way of com- and the whole of their azote, will consist of a 

bustion. It is requisite, therefore, for this much greater proportion of hydrogen, to- 

purpose, that the fatty matter should be pre- gether with caibon and a minute quantity of 

viously diffused in 12 times its weight of hot oxygen. This, according to the theory of 

water ; and the muriatic or acetous add is M. Fourcroy, constitutes Uie waxy matter, or 

preferable to the sulphuric or nitrous, llie adipocere, which, in combination with am- 

colour of the waxy matter is greyish ; and monia, forms the animal soap into which the 

tiiougfa exposure to the air, and also the ac- deed bodies are thus converted, 
tion of the oxygenated muriatic add, pro- Muscular fibre, macerated in dilute nitric 

duced an apparent whitenessi, it nevertheless add, and afterwards well washed in warm 

disappeared by subsequent fusion. No me- water, affords pure adipocere, of a light yeU 

thod was discovered by which it could be low colour, nearly of the consistence of taU 

permanently bleached. low, of a homogeneous texture, and of course 

The nature of this wax or fiit is different free from ammonia. This is the mode in 

from that of any other known substance of which it is now commonly procured for che- 

the like kind. When slowly cooled after fu- mical experiment. 

sion, its texture appears crystalline or shivery. This curious substance has been more re- 
like spermaceti ; but a speedy cooling gives bently examined by ChevreuL He found it 
it a semitransparency resembling virax. Upon composed of a small quantity of ammonia, 
tlie whole, nevertheless, it seems to approach potash, and lime, united to much margarine, 
more nearly to the former than to the latter and to a very little of another fatty matter dif- 
of these bodies. It has less smell than sper- ferent from that. Weak muriatic acid seizea 
maceti, and melts at 127^ F. ; Dr fiostock the three alkaline bases. On treating the 
says 92°. Spermaceti requires 6*> more of heat residue with a solution of potash, the marg». 
to fuse it (according to Dr Bostock 20^). rine is predpitated in the form of a pearly 
Hie spermaceti did not so speedily become substance, while the other fat remains dis- 
brittle by cooling as the adipocere. One solved. Fourcroy being of opinion that the 
ounce of alcohol, of the strength between 39 fatty matter of animal carcasses, the sub- 
and 40 degrees of Bauro6*8 aerometer, dis^ stance of biliary calculi, and spermaceti, were 
solved when bcnling hot 12 gros«of this sub- nearly identical, gave them the same name 
stance ; but the same quantity in like circum- of adipocere ; but it appears from the re- 
staiices dissolved only 30 or 36 grains of searches of M. Chevreul, that these substan- 
spermaceti. Tlie separation of these matters ces are very different from each other, 
was also remarkably different, the spermaceti In the Philosophical Transactions for 1813 
being more speedily deposited, and in a there is a very interesting paper on the above 
much more regular and crystalline form, subject, by Sir £. Home and Mr Brande. 
Ammonia dissolves it wltli singular fadlity, ' He adduces many curious facts to prove that 
and even in the cold, this concrete oil separates adipocere is formed by an incipient and in^ 
from the fiitty matter ; and by heat it forms a complete putrefaction. Mary Howard, aged 
'transparent solution, which is a true soap. 44, died on the 12th May 1790, and was 
But no excess of ammonia can produce such buried in a grave ten feet deep, at the east 
an effect with spermaceti. end of Shorediteh church-yard, ten feet to 

M. Fourcroy concludes his memoir with the east of the great common sewer, which 

some speculations on the change to which runs from north to south, and has always & 

animal substances in peculiar drcumstances current of water in it, the usual level of which 



ADI 117 AER 

feet below the level of ihe ground* \y death. Fat thus appears to be formeci iii 
and two feet above the level of the coffins in the intestines, and from thence received into 
the graves. In August 1811 the body was the circulation, and deposited in almost every 
taken up, with some others buried near it, part of the body. And as there appears to 
for the purpose of building a vault, and the be no direct channels by which any super- 
flesh in all of them was converted into adi- abundance of it can be thrown out of the 
pocere or spennaceti* At the full and new body, whenever its supply exceeds the con- 
Bsoon the tide raises water into the graves, sumption, its accumulation becomes a disease, 
wfaicfa at other times are dry. To explain and oflen a very distressing one. See Bi- 
the extraordinary quantities of fat or adipo- liary Concbetions, Margaune, and In- 
cere formed by animals of a certain intestinal testinal CONCREXiONSb 
construction. Sir £. observes, that the current A DI T, in mining, is a subterraneous pasa- 
of water which passes through their colon, age slightly inclined, alx>ut six feet high, and 
while the loculated lateral parts are full of two or three feet wide^ begun at the bottom 
solid niatter, places the solid contents in of a neighbouring valley, and continued up 
somewhat similar circumstances to dead bo- to the vein, for &e purpose of canying out 
dies in the banks of a common sewer. the minerals and drawing off the water. If 
The circumstance of ambergris, which con- the mine require draining by a steam-engine 
tuns 60 per cent of fat, being found in im- from a greater depth, the water need be raised 
Dense quantities in the lower intestines of the only to the level of the adit Tliere is a 
tpermaceci whales, and never higher up than good account of the Comith aditsy by Mr W. 
seven feet from ^e anus, is an undeniable Philips, Tirans. Geol. Soc. voL ii. ; and of 
proof of firt being formed in the intestines ; adits in general, article Galerie, Brogniart's 
and as ambeigris is only met with in whales Mineralogy, voL ii. 

oat of health, it is most probably collected ADOPTER. A vessel with two necks 

there from the absorfoenti, under the influence placed between a retort and a receiver, and 

of disease, not acting so as to take it into the serving to increase the length of the neck of 

constitution. In the human colon, solid the former. See Laboratory. 
masses of fisit are sometimes met with in a ADULARIA. See Felspar. 
Saaaed state of that canal, and are called AERATED ALKALINE WATER* 

scj/bala. A description and analysis by me See Acid (Carbonic). 
of a mass of ambergris, extracted in Perth- AERIAL ACID. See Acid (Carbo> 

shire from the rectum of a living woman, Nic). 

were published in a London Medical Journal AEROLITE, or Meteoric Stone. Sea 

in September 1817. lliere is a case com- Meteorite. 

nunicated by Dr Babington, of fat formed AEROMETER. Hie name given by 

in the intestines of a girl four and a half Dr M. Hall to an ingenious instrument of 

yeara old, and passing off by stooL Mr his invention, for making the necessary cot* 

Brmode found, on the suggestion of Sir E. rections in pneumatic experiments to asoer- 

Home^ that muscle cligested in bile, is con- tain the mean bulk of the gases. It consuts 

vertible into &t at the temperature of about c»f a bulb of glass 44 cubic inches capacity, 

100°. If the substance^ however, pass ra- blown at the end of a long tube whose capa^ 

pidly into putrefaction, no fiit is formed, city is one cubic inch, lliis tube is inserted 

Faeces. voided by a gouty gentleman after six into another tube of nearly equal length, sup- 

4]ays* constipation, yielded, on infusion in ported on a sole. The first tube is sustained 

water, a fittty film. This process of forming at any height within the second, by means of 

lat in the lower intestines by means of bile, a spring. Five cubic inches of atmospheric 

throws considerable light upon the nourish- air, at a medium pressure and temperature, 

aent derived from dystera,— « fact well as- are to be introduced into the bulb and tube, 

ffwtained, hot which could not be explained, of the latter of which it will occupy one-half: 

It also accounts for the wasting of the body the other half of this tube, and part of the 

wbidi fo invariaUy attends all complaints of tube into which it is inserted, are to be occu- 

Ifae lower bowels. It accounts, too» for all pied by the fluid of the pneumatic trough, 

the varieties in the turns of the colon, which whether water or mercury. The point of the 

meet with in so great a degree in different tube at which the air and fluid meet is to be 



animals. This pr op erty of the bile explains marked by the figure 5, denoting 5 cubic 
the formation of fiuty concretions in inches. The upper and lower halves of the 



the gall-bladder so commonly met with, and tube are each divided into five parts, repre- 

wfaich, from these experiments, appear to be aenting tenths of a cubic inch. The exter- 

pmduced by the action of the bile on the nal tube has a scale of inches attached. 

mucus secreted in the gall-bladder ; and it Journal of Scieneey vol. v. See Gas, and 

enablea us to understand how want of the Appendix. 

galUbladder in children, from malformation, AEROSTATION. A name commonly, 

is attended with excessive leanness, notwitli- but not very correctly, given to the art of 

landing a great i^petite^ and leads to an ear- raising heavy bodies into the atmosphere;, by 



AFF 



118 



AGA 



the buoyancy of heated air, or gases of small 
specific gravity, enclosed in a hag, ifiiiich, 
firom being usually of a spheroidal fonn, is 
called a balloon. Of all the possible shapes, 
the globular admits the greatest capacity under 
tiie least surface. Hence, of two bags of the 
same capacity, if one b^ spherical, and the 
other of any other shape, the former will con- 
tain the least quantity of cloth, or the least 
surface. The spheroidal form is therefore 
best fitted for aerostation. Varnished lute- 
string or muslin are employed for the en- 
Tdopes. The following table shows the re- 
lation betwixt the diameters, surfaces, and 
capacities of spheres : 

Dfameten. Surfinei. Cipsdtiei. 

1 a 141 0.523 

2 12.567 4.188 

3 2a274 14.137 

4 50.265 3a51 

5 78.54 65.45 
10 314u 159 52a6 
15 706.9 1767.1 
20 1256.6 4189. 
25 196a5 8181. 
30 2827. 14137. 
40 5026. 33510. 

Having ascertained by experiment the 
weight of a square foot of the varnished 
doth, we find, by inspection in the above 
table, a multiplier, whence we readily com^ 
pute the total weight of the balloon. A 
cubic foot of atmospheric air weighs 527 gr. 
and a cubic foot of hydrogen about &• 
But as the gas employed to fill balloons is 
never pure, we must estimate its weight 
at something more. And perhaps, taking 
every thing into account, we shall find it a 
convenient and sufificiently precise rule for 
aerostation, to consider every cubic foot of 
included gas to have by itself a buoyancy of 
fully one ounce avoirdupois. Hence a bal- 
loon of 10 feet diameter will have an ascen- 
sional force of fully 524 oz. or 33 lbs. minu» 
the weight of the 314 superficial feet of 
doth ; and one of 30 feet diameter, a buoy- 
ancy of fully 14137 oz., or nearly 890 lbs. 
minus tlie weight of the 2827 feet of cloth. 
On this calculation no allowance need be 
made for the seams of the balloon. See the 
article Varnish. 

^TITES, or Eagle Stone, is a name 
that has been given to a kind of hollow 
geodes of oxide of iron, often mixed with 
a larger or smaller quantity of silex and alu- 
mina, containing in their cavity some con- 
cretions, which rattle on shaking the stone. 
It is of a dull pale colour, composed of con- 
centric layers of various magnitudes, of an 
oval or polygonal form, and often polished. 
Eagles were said to carry them to their nests, 
whence their name ; and superstition formerly 
ascribed wonderful virtues to them. 

AFFINITY (CHEMICAL). See At- 
TEAcnoN (Chemical^. 



AGALMATOLITE. See BildsTein. 
' AGAKICUSb The mushroom, a genua 
of the order Fungi. Mushrooms appear to 
approach nearer to the nature of animal mat- 
ter than any other productions of the vege- 
table kingdom, as, beside hydrogen, oxygen, 
and carbon, they contain a considerable por- 
tion of nitrogen, and yield ammonia by dis- 
tillation. Prof. Proust has likewise disco- 
vered in them the benzene add, and phosphate 
of Ume. 

A few of the spedes are eaten in thia 
country, but many are recorded to have pro- 
duced poisonous effects. Perhaps it is of 
importance, that they should be fresh, tho- 
roughly dressed, and not of a coriaceous 
texture. Our ketchup is made by sprinkling 
mushrooms with salt, and letting them stand 
till great part is resolved into a brown liquor^ 
which is then boiled up with spices. 

In pharmacy two spedes of boleius have 
formerly been used under the name of aga- 
ric Tlie B, jnni lands, or maU agaric of 
the shops, was given as a purgative, dther in 
substance, or in an extract made with vine- 
gar, wine, or an alkaline solution: and thfl 
B, igtiiariusy spunk or touchwood, caUedye- 
male agaric, was applied externally as a styp- 
tic, even after amputations. For this purpose 
the soft inner substance was taken and beat- 
en with a hammer, to render it still softer. 
That of the oak was preferred. 

The mushrooms, remarkable for the quick- 
ness of thdr growth and decay, as well as for 
the fetor attending their spontaneous decom- 
position, were unaccountably neglected by 
analytical chemists, though capable of re- 
warding thdr trouble ; as is evinced by the 
recent investigations and discoveries of MM. 
Vauquelin and Braconnot The insoluble 
fungous portion of the mushroom, though it 
resembles woody fibre in some respects, yet 
being less soluble than it in alkalis, and 
yielding a nutritive food, is evidently a pe- 
culiar product, to which accordingly the name 
of fungin has been given. Two new vege- 
table adds, the boletic and fungic, were i^ 
fruits of these researches. 

1. Agaricus campcstris, an ordinary ar- 
ticle of food, analyzed by Vauqudin, gave 
die following constituents:— 1. Adipocere. 
On expressing the juice of the agaric, and 
subjecting the remainder to the action of 
boiling alcohol, a fatty matter is extracted, 
which falls down in white flakes as the alco- 
hol cools. It has a dirty white colour, a 
fatty fed like spermaceti, and, exposed to 
heat, soon melts, and then exhales the odour 
of grease. 2. An oil jr matter. 3. Vegetable 
albumen. 4. The sugar of mushrooms. 
5. An animal matter soluble in water and 
alcohol : on bdng heated it evolves the odour 
of roasting meat, like osmazoroe. 6. An ani- 
mal matter not soluble in alcohol. 7. Fun- 
gin. 8. Acetate of potash. 



AGA 119 AGA 

2. ^gofieuM voivaeeut affbrded Braoonnot a dreadful deUriuni, and acute pains, acccnn- 
fungin, geladn, vegecable albumen, much panied them to the last momenL One of 
phosphate of potash, some acetate of potash, them sunk a few hours after his admission into 
sugar of mushrooms, a brown oil, adipocere, the hospital; the three others had th6 same 
wax, a very fugacious deleterious matter, un- fiite in tbe course of the night. On opening 
conlbined acid, supposed to be the acetic, their dead bodies, the stomach and intestines 
benzoic add, muriate of potash, and a deal displayed large spots of inflammation and 
of water; in all 14 ingredients. gangrene; and putrefaction seemed advanc- 

3. Jgaticui acris or piperahts, was found ing very rapidly. 

by Braconnot, after a minute analysis, to AGA KICUS MINER ALIS, the m<mfi* 

contain nearly the same ingredients as the tain milk or mowtiain meat of the Germans, 

preceding, without the wax and bensoic add, is one of the purest of the native carbonates 

but with more adipocere. of lime, found chiefly in the clefts of rocks, 

4. Agarieus Mtt^pticut. From twenty parts and at the bottom of some lakes, in a loose 
of this Braconnot obtained of resin and adi- or semi-indurated form. It has been used 
pooere 1.8, fungin 16.7, of an unknown ge- internally in hflraaorrfaages, strangury, gravel, 
latinous substance, ^ potash salt, and a fuga- and dysenteries ; and externally as an appli- 
doua acrid prindple 1.5. cation to old ulcers, and weak and watery 

5. Agqiicus bulbotus was examined by eyes. 

Vauquelin, who found the following consti- M. Fabroni calls by the name of mineral 

tuents ;— an animal matter insoluble in alco- ogariCf or/bstii meal, a stone of a loose con- 

hoi, osmazome, a soft fatty matter of a yel- sistence found in Tuscany in considerable 

low colour and acrid taste, an arid salt (not abundance, of which bricks may be made^ 

a phosphate). The insoluble substance of ^^^ with or without the addition of a twen- 

tfae agaric yielded an add by distillation. Tn ^^^ P"*^ ^^ *>^gil> m> ligbt as to float in 

Orfila*s Toxicology several instances are de- water; and which he supposes the andents 

tailed of the fatal effects of this species of ^"^ ^^ making their floating bricks. This, 

mushroom on the human body. Dogs were however, is very different from tlie preceding, 

killed within 24 hours by smidl quantities of p^ ^>^g even of the calcareous genus, since 

it in substance, and also by its watery and '^ 'PP^ars, on analysis, to consist of silex 55 

alcoholic infusions; but water distilled from P*'^ magnesia 15^ water 14, argil 12, lime 

it waa not injurious. It is curious that the ^ ^° ^' Kirwan calls it argitlo-muriie, 
animab experienced little inconvenience after AGATE. A mineral, whose basis is cal- 

swallowing it, during the first ten hours ; cedony, blended with variable proportions of 



r, cholera, convulsions, and painful j^per, amethyst, quartz, opal, heliotrope, and 

cramps, are the usual symptoms of the poison cornelian. — Ribbon agate consists of alternate 

in men. The best remedy is an emetic '^ parallel layers of calcedony with jasper, 

6. Agarieus theogolut. In this Vauquelin (puutz, or amethyst The most beautiful 
found sugar of mushrooms, osmazome, a bit- come* from Siberia and Saxony. It occurs 
ter acrid fatty matter, an animal matter not ^^ porphjrry and gndss. — Brecciated agate g 
soluble in alcohol, a salt containing a vegeta^ \ ^^"^ of amethyst, containing fragments of 
ble add. ribbon agate, constitute thb beautiful variety. 

7. Agarieus muscarius. Vauquelin's ana- ^^ 1^ <f Saxon origin.—- ForCt/Scofion agate is 
lysis of this spedes is as follows :^The two fouod in nodules of various imitative shapes, 
animai matters of the last agaric, a fatty imbedded in amygdaloid. This occurs at 
matter, sulphate^ phosphate, and muriate of Oberstein on the Rhine, and in Scotland, 
potash, a volatile add from the insoluble ^° cutting it across, and polishing it, the in- 
matter. The following account from Orfila, terior sig-zag parallel lines bear a considerable 
of the effects of this spedes on the animal resemblance to the plan of a modem fortifi- 
coonomy b interesting. Several F^nch sol- cation. In the very centre, quartz and ame- 
diers ate, at two leagues from Polosck in thyst are seen in a splintery mass, surrounded 
Ruasia, mushrooms ofthe above kind. Four hy the jasper and calcedony.— il/oc//a stone* 
of them, of a robust constitution, who con- TVanslucent calcedony, containing dark out- 
cetved themselves proof against the conse- lines of arborization, like vegetable filaments, 
qnences under which their feebler companions >> called Mocha stone, from the place in 

beginning to suffer, refused obstinately Arabia where it is chiefly found. These cu- 



to take an emetic. In the evening the fol- rious appearances were ascribed to deposits of 

lorwing symptoms appeared :— Anxiety, sense >n>n or manganese^ but more lately they have 

of suflfbcation, ardent thirst, intense griping heen thought to arise from mineralized pUmts 

pains, a small and irregular pulse, universal of the cryptogamous class.— Afoit agate is a 

cold sweats, changed expression of counte- calcedony with variously coloured ramifica- 

nance, violet tint of the nose and lips, general tions of a vegetable form, occasionally tra- 

trembling, fedd stools. The symptoms be^ versedwithirregular veins of red jasper. Dr 

coming worse, they were carried to the hospi- M'CuUoch has recently detected, what Dau- 

taL Coldness and liyid colour of the limbs, benton merely conjectured, in mocha and 



AGG 



IW 



AIR 



mosB agaiw, aquatic confenre» unaltered both 
in colour and fonn, and also coated with iron 
oxide. . Mosses and lichens have also been 
obaenred, along with chlorite, in vegetations. 
An onyx agate set in a ring, belonging to the 
Earl of Powis, contains the chrysalis of a 
moth. Agate is found in most countries, 
chiefly in trap rocks, and serpentine. Hollow 
nodules of agate, called geodes, present inte- 
riorly crystals of quarts, colourless or ame- 



be conceived to remain{without diange ; and 
beyond these, any further subdivision cannot 
be made without developing the component 
parts, namely, the alkali and the acid ; vrhich 
are still further resolvable into their consti- 
tuent principles. 

AGRICULTURE, considered as a de- 
partment of chemistry, is a subject of vast 
importance, but hitherto much neglected. 
When we consider tliat every change in the 



thystine, having occasionally scattered crystals arrangements of matter connected with the 

of stilbite, chabasie, and capillary mesotype. growth and nourishment of plants; thecom- 

Hiese gcodes are very common. Bitumen parative values of their produce as food ; the 

lias been found by M. Patrin in the inside of composition and constitution of soils ; and the 

some of them, among the hills of Dauria, on manner in which lands are enriched by ma- 



the right bank of the Chilca. The small 
geodes of volcanic districts contain water oc- 
casionally in their carities. These are chiefly 
found in insulated blocks of a lava having an 
eardiy fracture. When they are cracked, the 
liquid escapes by evaporation: it is easily 



nure, or rendered fertile by the different pro- 
cesses of cultivation,— we shall not hesitate to 
assign to diemical agriculture a high place 
among the studies of man. If land be un- 
productive, and a system of ameliorating it is 
to be attempted, the sure method of attaining 



restored by plunging them for a little in hot this object is by determining the causes of its 



water. Agates are artificially coloured by 
immersion in metallic solutions. Agates were 
more in demand formerly than at present. 
They were cut into cups and plates/or boxes ; 
and also into cutlass and sabre handles. They 
are still cut and polished on a considerable 
scale, and at a moderate price, at Oberstein. 
Hie surface to be polished is first coarsely 
ground by large millstones of a hard reddish 
sandstone, moved by water. The polish is 
afterwards given on a wheel of soft wood. 



sterility, which must necessarily depend upon 
some defect in the constitution of the soil, 
which may be easily discovered by chemical 
analysis. Some lands of good apparent tex- 
ture are yet eminently barren ; and common 
observation and common practice afford no 
means of ascertaining the causes, or of re- 
moring the effect The application of che- 
mical tests in such cases is obvious ; for the 
soil must contain some noxious principle, 
which may be easUy discovered, and probably 



moistened and imbued with a fine powder of easily destroyed. Are any of the salts of 



a hard red trifutU found in the neighbourhood. 
M. Faujas thinks that this trijHdi is produced 
by the decomposition of the porphyrated rock 
that serves as a gangue to the agates. Hie 
ancients employed agates for making cameos. 
(See Calcedony.) Agate mortars are valu- 
ed by analytical chemists, for reducing hard 
minerals to an impalpable powder. For some 
interesting optical properties of agates, see 

LlOBT. 

The oriental agate is almost transparent, 
and of a ritreous appearance. The occidental 
is of various colours, and often veined with 
quartz or jasper. It is mostly found in small 
pieces covered wiih a crust, and often running 
in veins through rocks like flint and petro- 



iron present? They may be decomposed by 
lime. Is there an excess of siliceous sand? 
The system of improvement must depend on 
the application of clay and calcareous matter. 
Is there a defect of calcareous matter ? The 
remedy is obvious. Is an excess of vegetable 
matter indicated? It may be removed by 
liming, paring, and burning. Is there a defi- 
ciency of vegetable matter ? It is to be sup- 
plied by manure. Peat earth is a manure ; 
but there are some varieties of peats whidi 
contain so large a quantity of ferruginous 
matter as to be absolutely poisonous to plants. 
There has been no question on which more 
difference of opinion has existed, than that 
of the state in which manure ouj^t to be 



silex, from which it does not seem to differ ploughed into land ; whether recent, or when 



greatly. Agates are most prized, when the 
internal figure nearly resembles some animal 
or plant. 

AGGREGATE. When bodies of the 
same kind are united, the only consequence 
U, that one larger body is produced. In tbb 
case» the unit^ mass is called an aggregate, 
and does not differ in its chemical properties 
from the bodies from which it was originally 



it has gone through the process of fermenta- 
tion. But whoever will refer to the simplest 
principles of chemistry, ci^nnot entertain a 
doubt on the subject. As soon as dung be- 
gins to decompose, it throws off its volatile 
parts, which are the most valuable and most 
efficient. Dung which has fermented so as 
to become a mere soft cohesive mass, has 
generally lost from one-third to one^half of 



made. Elementary writers call the smallest its most useful constituent elements. • See the 

parts into which an aggregate can be dirided, articles Analysis, Mandre, Soils, Veoe- 

without destroying its chemical properties, in- tation, and Sir H. Davy*s jigricuUural 

tegrant parts. Thus the integrant parts of ChemiHry, 
common salt are the smallest parts which can AIR was, till lately, used as the generic 



AIR. 121 AIR 

name fbr tncfa inriiible and ezoeedbgly rara znaintaiiiiiig aoy combuidon for a second 
fluids as posBHs a Yery high degree of elas- time, or of supporting the life of anhnals. 
tidky, and are not condensable into the liquid The respiration of animals produces the 
state by any degree of cold hitherto produced ; same effect on atmospherical air as combus- 
bat as this term is conunonly employed to tion does. When an animal is included in 
signify that compound of aeriform fluids a limited quantity of atmospherical air, it dies 
nhich constitutes our atmosphere, it has been as soon as the oxygen is consumed ; and no 
deemed advisable to restrict it to this signiii- other air will maintain animal life but ozy- 
cation, and to employ as the generic term gen, or a mixture which contains it. Pure 
the word Gab, (which see), for the different oxygen maintains the life of animals much 
kinds of air, except what relates to our at- longer than atmospherical air, bulk for bulk, 
mospheric compound. It is to be particularly observed, however, 
AIR (ATMOSPHERICAL or COM- that, in many cases of combustion, the oxy. 
MON). The immense mass of permanently gen of the air, in combining vritb the corn- 
elastic fluid whidi surrounds tlie globe we bustible body, produces a compound, not solid 
inhabit, must consist of a general assemblage or liquid, but aeriform. The residual air will 
of every kind of air which can be formed by therefore be a mixture of the nitrogen of the 
the various bodies that compose its surface, atmosphere vrith the consumed oxygen, con- 
Most of these, however, are absorbed by wa- verted into another gas. Thus, in burning 
ter; a nurob<»' of them are decomposed by charcoal, the carbonic acid gas generated, 
combination vrith each other ; and some of mixes with the residual nitrogen, and makes 
them are seldom disengaged in considerable up exactly, when the effect of heat ceases, 
quantities by the processes of nature. Hence the bulk of the original air. The breathing 
It is that the lower atmosphere consists chiefly of animals, in like manner, changes the oxy- 
«f oxygen and nitrogen, together vrith mois- gen into carbonic acid gas, without altering 
ture and the occasional vapours or exhala- the atmospherical volume, 
tions of bodies. There are many provisions in nature, by 

That the air of the atmosphere is so trans- which the proportion of oxygen in the atmo»> 
parent as to be invisible, except by the blue phere, which is continually consumed in re- 
colour it reflects when in very large masses, spiradon and combusdon, is again restored 
aa is seen in the sky or region above us, or to that fluid. In fact there appears, as far as 
in viewing extensive landscapes ; that it is an estimate can be formed of the great and 
without smell, except that of electricity, which general operadons of nature^ to be at least as 
it Bomedmes very manifestly exhibits ; alto- great an emission of oxygen, as is suflldent 
gether without taste, and impalpable ; not to keep the general mass of the atmosphere 
condensable by any degree of cold into the at the same degree of purity. Most plants 
dense fluid state, though easily changing its emit oxygen in the sunshine. Lastly, if to 
dimensions with its temperature ; that it gr»- this we add the decomposition of water, there 
Titates and is highly elastic ;-^are among the will be numerous occasions in which this 
numerous observations and discoveries which fluid will supply us with disengaged oxygen ; 
do honour to the sagacity of the philosophers vvhile, by a very rational supposition, its hy- 
of the seventeenth century. Iliey likewise drogen may be considered as having entered 
knew that this fluid is indispensably neces- into the bodies of plants, for the formation 
sary to combustion ; but no one, except the of oils, sugars, mucilages, &c from which it 
great, though neglected John Mayow, ap- may be again extricated, 
pears to have formed any proper notion of To determine the respirability or purity of 
its manner of acting in that process. air, it is evident that recourse must be had to 

The air of the Httmosphere, like other its comparative efllcacy in maintaining corn- 
fluids, appears to be capable of holding bodies bustion, or some other equivalent process, 
in solution. This subject will be considered under the ar- 

Mere heating or cooling does not affect the tide Eudiometer. 

chemical properties of atmospherical air ; but From the latest and most accurate experi- 

actual combustion, or any process of the same ments, the proportion of oxygen in atmos- 

nature, combines its oxygen, and leaves its pheric air is by measure about 21 per cent; 

nitrogen separate. Whenever a process of and it appears to be very nearly the same 

this kind is carried on in a vessel containing whether it be in this country or on the coast 

atmospherical air, which is enclosed either by of Guinea, on low plains or lofty mountains, 

inverting the vessel over mercury, or by stop- or even at the height of 7250 yards above the 

ping its aperture in a proper manner, it is level of the sea, as ascertained by Gay Lussac 

found that the process ceases sAer a certain in his aerial voyage in September 1805. The 

time ; and that the remaining air (if a com- remainder of the air is nitrogen, with a small 

bustible body capable of solidifying the oxy- portion of aqueous vapour, amounting to 

gen, such as phosphorus, have been employ- about 1 per cent in the driest weather, and a 

«d) has lost about a fifth part of its volume, still less portion of carbonic add, not exoeed- 

and b of such a nature as to be incapable of ing a thousandth part of the whole. 



AIR 



122 



ALA 



As oxygen and nitrogen diflRnr in sped- 
6c gravity in the proportion of 1.1 III to 
0.9722, it has been presumed, that the oxy- 
gen would be more abundant in the lower 
regions, and the nitrogen in the higher, if 
they constituted a mere mechanical mixture ; 
which appears contrary to the fact On the 
other hand it has been urged, that they can- 
not be in the state of chemical combination, 
because they both retain their distinct pro- 
perties unaltered, and no change of tempera- 
ture or density takes place on their union. 

To get rid of the difficulty, Mr Dalton of 
Manchester framed an ingenious hypothesis, 
that the particles of different gases neither 
attract nor repel each other; so that one gas 
expands by the repulsion of its own particles, 
without any more interruption from the pre- 
sence of another gas, than if it were in a va- 
cuum. This would account for the state of 
atmospheric air, it is true ; but it does not 
agree with certain facts. In the case of the 
carbonic acid gas in the Grotto del Cano, and 
over the surface of brewers* vats, why does 
not this gas expand itself freely upward, if 
the superincumbent gases do not press upon 
it ? Mr Dalton himself, too^ instances as an 
argument for his hypothesis, that oxygen and 
hydrogen gases, when mixed by agitation, do 
not separate on standing. But why should 
either oxygen or hydrogen require agitation, 
to diffuse it through a vacuum, in which, ac- 
cording to Mr Dalton, it is placed? 

The theory of BerthoUet appears consis- 
tent with all the facts, and sufficient to ac- 
count for the phenomenon. If two bodies 
be capable of chemical combination, their 
particles must have a mutual attraction for 
each other. This attraction, however, may 
be so opposed by concomitant circumstances, 
that it may be diminished in any degree. 
Tlius we know, that the affinity of aggrega- 
tion may occasion a body to combine slowly 
with a substance for which it has a powerful 
affinity, or even entirely prevent its combine 
ing with it; the presence of a third substance 
may equally prevent the combination; and 
so may the absence of a certain quantity of 
caloric But in all these cases the attraction 
of the particles must subsist, though dimi- 
nished or counteracted by opposing circum- 
stances. Now we know that oxygen and 
nitrogen are capable of combination ; their 
particles, therefore, must attract each other ; 
but in the circumstances in which they are 
placed in our atmosphere, that attraction is 
prevented from exerting itself to such a de- 
gree as to form them into a chemical com^ 
pound, though it operates with sufficient force 
to prevent their separating by their difference 
of specific gravity. ITius the state of the 
atmosphere is accounted for, and every dif- 
ficulty obviated, without any new hypothe- 
sis. 

The exact specific gravity of atmospherical 



air, compared to that of water, is a very nice 
and important problem. By reducing to 60^ 
Fahr. and to 90 inches of the barometer, the 
resulto obtained with great care by MM. Biot 
and Arago, the specific gravity of atmos- 
pherical air appears to be 0.001220, water 
being represented by 1.000000. Tliis relation 
expressed fractionally is -g^?* <"' w>ter is 820 
times denser than atmospherical tar, Mr Rice, 
in the 77th and 78th numbers of the Annals 
of Philosophy, deduces from Sir Greorge 
Shuckburgh*s experiments 0.00120655 for 
the specific gravity of air. Tliis number 
gives water to air as 827.437 to 1. If with 
Mr Rice we take the cubic inch of water ss 
252.525 gr. then 100 cubic inches of air by 
Biot's experimento will weigh 30.808 grains, 
and by Mr Rice's estimate 30.519. He con- 
siders with Dr Prout the atmosphere to be a 
compound of 4 volumes of nitrogen and 1 of 
oxygen ; the specific gravity of the first being 
to that of the second as l.llll to 0.9722. 
Hence 

0.8 vol nitr. sp.gr. 0.001 166= 0.000a?3 
0.2 oxy. 0.001340=0.000268 

0.001201 

The numbers are transposed in the Annals 
of Philosophy by some mistake. 

MM. Biot and Arago found the spedflc 
gravity of oxygen to be - 1. 10359 

and that of nitrogen, - 0.96913 

air being reckoned - 1.00000 

Or compared to water as um'ty,^ 

Nitrogen is 0.001 182338 

Oxygen, 0.001346879 

And 0.8 nitrogen = a00094587 

0.2 oxygen = 0.00026927 



And 0.79 nitrogen 
0.21 oxygen 



a00121514 

rzr 0.000934 
= 0.000283 



0.001217 
A number which approaches very nearly to 
the result of experiment Many analogies, 
it must be confessed, favour Dr Prout*s pro- 
portions ; but the greater number of experi- 
ments on the composition and density of the 
atmosphere agree with Biot*s results. No- 
thing can decide these fundamental chemical 
proportions, except a new, elaborate, and 
most minutely accurate series of experiments. 
We shall then know whether the atmosphere 
contains in volume 20 or 21 per cent of oxy- 
gen. See Equivalents, and Gas. 

ALALITE. See Diofside. 

ALABASTER. Among the stones which 
are known by the name of marble, and have 
been distinguished by a considerable variety 
of denominations by statuaries and others, 
whose attention is more directed to their ex- 
ternal character and appearance than their 
component parts, alabasters are those which 



ALB 



183 



ALB 



hKte a gretter or less degree of imperfect 
tnnsgmncyf a granular tezturei are softer, 
take a duller polish than maible, and are 
usually of a whiter colour. Some stones, 
however, of a veined and ctdoured appear- 
ance^ have been considered as alabaster, from 
their posaesaing the first mentioned criterion ; 
and some trani^parent and yellow sparry stones 
have also receiyed this appellation. 

M. Tissot hardens plaster casts and alabas- 
ter, by drying them hard in a baker's oven 
for twenty-four hours or longer, according 
to their thickness ; withdrawing and cooling 
them ; then dipping them twice in river w»- 
ter for a minute or two each time. The 
piece is then exposed to the air, and at the 
end of three or four days it acquires the 
hardness and density of marble^ so as to bear 
polishing. 

ALBIN. A mineral cliscovered at Mo- 
nabefg, near Auadg, in Bohemia ; and being 
of an opaque white colour, has been called, 
by Werner, jUbhu Aggregated crystalline 
i<w«ifiM» constitute masdve albin. Snudl crys- 
tals of it in right prisms, whose summits con- 
sist of four quadiangular planes, are found 
sprinkled over mammelated masses in cavi- 
ties. See Zeoute. 

ALBIT£. A mineral, in crystals fre- 
quently, or almost always, met under the 
form of hemitrop^i. These hemitropes are 
formed when two crystals are so joined to each 
otiier, that the upper plane of the one is ap- 
plied upon the inferior plane of the other. 
See Clbatelanixte, which is the name now 
riven to this minersL 

ALBUM GRiBCUM. Hie white and 
solid excrement of dogs which subsist chiefly 
on bones, was received as a remedy in the 
medical art, under the name of Album Gras- 
cum. It consists, for the most part, of the 
earth of bones or lime, in combination with 
phosphoric acid. 

ALBUMEN. This substance, which de- 
rives its name from the Latin .for the white of 
an egg, in which it exists abundantly, and in 
its purest natural state, is one of Uie chief 
constituent principles of all the animal solids. 
Beside the white of egg, it abounds in the 
serum of blood, the vitreous and crystalline 
humours of the eye, and the fluid of dropsy. 
Fonrcroy claims to himself the honour of 
having discovered it in the green feculse of 
plants in general, particularly in those of the 
cruciform order, in very young ones, and in 
the fresh shoots of trees, though Rouelle ap- 
pears to have detected it there long before. 
Vauquelin says it exists also in the mineral 
water of Flombieres. 

M. Seguin has found it in remarkable 
quantity in such vqpetables as fennent vrith- 
out yeast, and afford a vinous liquor ; and 
from a series of experiments he infers, that 
albumen is the true principle of fermentation, 
and that its action is more powerfrU. in pro- 



portion to Its solubility, three different de- 
grees of which he found it to possess. 

Hie chief characteristic of albumen is its 
coagulability by the action of heat. If the 
white of an egg be exposed to a heat of about 
134° F. white fibres begin to appear in it, and 
at 160^ it coagulates into a solid mass. In a 
heat not exceeding 21 2<^ it dries, shrinks, and 
assumes the appearance of horn. It is soIuf^ 
ble in cold water before it has been coagu- 
lated, but not after; and when diluted with 
a very large portion, it does not coagulate 
easily. Pure alkalis dissolve it, even after 
coagulation. It is precipitated by muriate 
of mercury, nitro-rouriate of tin, acetate of 
lead, nitrate of silver, muriate of gold, infu- 
sion of galls, and tannin. The adds and 
metallic oxides coagulate albumen. On the 
addition of concentrated sulphuric add, it 
becomes black, and exhales a nauseous smelL 
Strong muriatic add gives a violet tinge to 
the coagulum, and at length becomes satu- 
rated with ammonia. Abotit 7 or 8 parts 
of add to one part of albumen, cause a most 
intense blue colour, even at a low temper- 
ature; but its development is favoured by 
a temperature of about 80^ F. Nitric add, 
at 7(P F., disengages from it abundance of 
azotic gas ; and if the heat be increased, 
prussic add b formed, after which carbonic 
add and carburetted hydn^^ are evolved, 
and the residue consists of water containing a 
little oxalic add, and covered witli a lemon- 
coloured fat oil. If dry potash or soda be 
triturated witii albumen, dther liquid or solid, 
ammoniacal gas is evolved, and the caldna- 
tion of the residuum yields an alkaline pru»- 
siate. 

On exposure to the atmosphere in a moist 
state, albumen passes at once to the state of 
putrefaction. 

Solid albumen may be obtained by agitat- 
ing white of egg with ten or twelve tiroes its 
weight of alcohoL This sdzes the water 
which held the albumen in solution; and 
this substance is precipitated under the form 
of white flocks or filaments, which cohesive 
attraction renders insoluble, and which con- 
sequentiy may be freely washed with water. 
Albumen thus obtained is like fibrine^ solid, 
white, insipid, inodorous, denser than water, 
and without action on vegetable colours. It 
dissolves in potash and soda more easily 
than fibrine ; but in acetic add and ammo- 
nia, with more diflSculty. When these two 
animal prindples are separately dissolved in 
potash, muriatic add added to the albumin- 
ous does not disturb the solution, but it pro- 
duces a cloud in the other. 

Fourcroy and several other chemists have 
ascribed the characteristic coagulation of al- 
bumen by heat to its oxygenation. But co- 
hesive attraction is the real cause of the phe- 
nomenon. In proportion as the temperature 
rises, the particles of water and albumen re- 



ALB 124 ALC 

cede from each other, their affinity diminuhei^ As albumen occaiidnt )predpitatea with the 

and then the albumen predpitatea. However, aolutions of almost every meUllic salt, pro- 

by uniting albumen with a large quantity of bably it may act beneficially against other 

water, we diminish its coagulating property to species of mineral poison, 
such a d^ree, that heat renders the solution From its coagulability albumen is of great 

merely opalescent A new-laid egg yields a use in clarifying liquids. See Claeifica- 

soft coagulum by boiling; but when, by keep- tion. 

ing, a portion of the water has transuded so as It is likewise remarkable for the property 

to leave a void space within the shell, the con- of rendering leather supple, for which pur- 

centrated albumen affords a firm coagulum. pose a solution of whites of eggs in water is 

An analogous phenomenon is exhibited by used by leather-dressers ; and hence Dr Lobb, 

acetate of alumina, a solution of which, being of Yeovil in Somersetshire, was induced to 

heated, gives a precipitate in Bakes, which re- employ this solution in cases of contraction 

dissolve as the caloric which separated the par- and rigidity of the tendons, and derived from 

tides of acid and base escapes, or as the tern- it apparent success. 

perature falls. A solution containing 1-lOth Vegetable albumen has an almost perfect 

of dry albumen forms by heat a solid coagu- resembUnce to white of egg. It dissolves in 

lum ; but when it contains only 1- Idth, it gives alkalis, and when in excess the solutions are 

a glairy liquid. One thousandth part, how- neutraL It then coagulates slightly by heat, 

ever, on applying heat, occasions opalescence, but the prindpal part is retained in solution : 

Putrid white of egg, and the jms of ulcers, it combines with adds, and when exactly s»- 

faave a similar smelL According to Dr Bos- turated, the substance remains soluble, but ex- 

tock, a drop of saturated solution of cor- cess of add (except the acetic and phospbo- 

rosive sublimate let fall into water containing ric) pradpitates it Prior to the action of 

W?? of albumen, occasions a milkiness and potash, the vegetable albumen dissolves feebly 

curdy predpitate. On adding a slight excess in vinegar or phosphoric add ; but by ebull^ 

of the mercurial solution to the albuminous ^on with tliese acids, it forms a transparent 

liquid, and applying heat, the precipitate colourless jelly of considerable volume. Sou- 

which falls, bdng dried, contains in every 7 bdran has shown, that the axotized prinriple 

parts, 5 of albumen. Hence that salt is the contained in emulsive seeds, and.particulwly 

most delicate test of this animal product in almonds, has all the properties of white of 

Tlie yellow pitchy predpitate occasioned by egg « it is in fact the same substance as ve- 

tannin is brittle when dried, and not liable to getable albumen. Vegetable albumen may 

putrefaction. But tannin, or infusion of he procured by the following process:^ 

galls, is a much nicer test of gdatin than of Boil gluten with successive portions of alco- 

albumen. hoi, until the latter ceases to become turbid 

Phosphoric acid recently prepared, either by cooling : mix these solutions with water, 
by the action of nitric acid or phosphorus, and distil ; as the aqueous residuum cools, a 
or by combustion in air, caused an abundant glutinous coherent mass will separate, re- 
predpitate in albumen. Recently ignited sembling gluten. It is vegetable gelatin^ 
phosphoric acid has always this effect ; but imd the same substance as that separated by 
after bdng kept in solution for a few days, it Einhof *s process from barley, &c The sub- 
loses that property. stance insoluble in alcfohol, is vegetable atbu* 

The cohesive attraction of coagulated al- men* 
bumen makes it resist putrefaction. In this ALBURNUM. ITie interior white bark 

state it may be kept for weeks under water of trees. 

without suffering change. By long digestion ALCARRAZASb A spedes of porous 
in weak nitric acid, albumen seems convert!- pottery made in Spain, for the purpose of 
ble into gdatin. By the analysis of Gay Lus- cooling water by its transudation and copious 
sac and Hienard, 100 parts of albumen are evaporation from tlie sides of the vessel. M. 
formed of 52.883 carbon, 23.872 oxygen, Darcet gives the following as the analysis of 
7.540 hydrogen, 15.705 nitrogen; or in theclay which is employed for the purpose:^' 
other terms, of 52.883 carbon, ^. 127 oxy- 60 calcareous earth, mixed with alumina and 
gen and hydrogen, in the proportions for con- a little peroxide of iron, and 36 of siliceous 
stituting water, 15.705 nitrogen, and 4.285 eartli, mixed with a liule alumina. In work- 
hydrogen in excess. The n^ative pole of a ing up the earths with water, a quantity of 
voltaic pile in high activity coagulates albu- «<^lt is added, and dried in it The pieces are 
men ; but if the pile be feeble, coagulation -only half baked. 

goes on only at the positive surface. Albu- ALCHEMY. A title of dignity, given 

men, in such a sUte of concentration as it in the dark ages, by the adepts, to the mysti- 

«xists in serum of blood, can dissolve some ^ cu^ hy which they professed to find the 

metallic oxides, particularly the protoxide of philosopher's stone, that was to transmute 

iron. Orfila has found white of egg to be hase metals into gold, and prepare tiie elixir 

the best antidote to the poisonous effects of of life. Though avarice^ fraud, and folly, 

corrosive Sublimate on the human stomach. v«<v ^^Msr motives, yet thdr experimental 



ALC 1^ ALC 

Tttevches were instrumental in promoting Whatever be the grain employed, it mutt 
the progress of chemical discorefy. Hence, be coarsely ground, imd then mixed carefully 
in particular, metallic pharmacy derived its with a little cold water, to prevent its run- 
origin, ning into lumps : water about 14(P F. may 

ALCOHOL. This term is applied to the then be added, till it is sufficiently mashed ; 

pure spirit obtainable by distillation from all and to the drained-off wort, yeast is added, 

liquids that have undergone vinous ferment»> The wort is allowed to ferment in a covered 

tion. vessel, to which, however, the air can have 

It appears to be essential to the fermen- access. Attention must be paid to the tern- 

tation of alcohol, that the fermenting fluid perature : for if it exceed 87^ F. the fermen- 

should contain saccharine matter, which is tation will be too rapid ; if it be below 60^, 

indispensable to that species of fennentation the fennentation will cease. The mean be- 

• called vinous. In France, where a great deal tween these will generally be found most fa- 
of wine is made^ particularly at the com- vourable. In this country it is the more 
mencement of the vintage, that is too weak common practice to mash the grain as for 
to be a saleable commodity, it is a common brewing malt liquors, and boil the wort. But 
practice to subject this wine to distillation, in in whichever way it be prepared, or if the wash 
order to draw off the spirit; and as the es- (so tlie liquor intended for distillation is called) 
sential oil that rises in this process is of a be made from melasses and water, due atten- 
mcMne pleasant flavour than that of malt or tion must be paid to the fermentation, that it 
melasses, the French brandies are preferred be continued till the liquor grows fine, and 
to any other ; though even in the flavour of pungent to the taste, which will generally be 
these there is a diflTerence, according to the about the third day, but not so long as to per- 

• vrine from which they are produced. In the mit the acetous fennentation to commence. 
West Indies a spirit is obtained from the juice In this state the wash is to be committed 
of the sugar-cane, which is highly impreg- to the still, (of which, including the head, it 
nated with its essential oil, and well known should occupy at least three^fourths), and dis- 

.by the name of mm. The distillers in this tilled with a gentle heat as long as any spirit 

country use grain, or melasses, whence they comes over, which will be till about half the 

distinguish the products by the name of malt wash is consumed. The more slowly the 

spiriit and meiastes spirits. distillation is conducted, the less will the pro- 

As the process of malting develops the sac- duct be contaminated with essential oil, and 
cfaarine principle of grain, it would appear to the less danger will there be of empyreuma. 
render it fitter for the purpose ; though it is A great saving of time and fuel, however, 
the common practice to use about six parts may be obtained by making the still very 
of raw grain with on^ of malt. For this two broad and shallow, and contriving a free exit 
reasons may be assigned : by using raw grain for the steam. This was at one time carried 
the expense of malting is saved, as well as to such a pitch in Scotland, that a still mea- 
tfae duty on malt ; and the proceis of malting suring 43 gallons, and containing 16 gallons 
requires some nicety of attention, since, if it of wash, has been charged and worked no less 
be carried too far, part of the saccharine mat- than four hundred and eighty times in the 
ter is lost, and if it be stopped too soon, this space of 24 hours. Thia would be incredi- 
SDsMer will not be wholly developed. Besides, ble, were it not established by unquestionable 
if the malt be dried too quickly, or by an un- evidence. See Laboratoay, article Still. 
equal heat, the spirit it yields will be less in The above wonderful rapidity of distillation 
quantity, and more unpleasant in flavour, has now ceased, since the excise duties have 
Another object of economical consideration been levied on the quantity of spirit produc- 
ts, what grain will afford the most spirit in ed; and not, as formerly, by the size of the 
proportion to its price, as well as the best in still. Hence, too, the spirit is probably im- 
quality. Barley appears to produce less spirit proved in flavour. 

than wheat ; and if three parts of raw wheat The firet product, technically termed low 

be mixed with one of malted barley, the pro- wi'ntf, is again to be subjected to distillation ; 

duce is said to be particularly fine. This is the latter portions of what comes over, called 

the practice of the distillers in Holland for Jeints, being set apart to be put into the wash- 

producing a spirit of the finest quality ; but still at some future operation. Tlius a large 

in £ngland they are expressly prohibited from portion of the watery part is left behind, 

using more than one part of wheat to two of Hiis second product, termed raw spirit^ being 

other grain. Rye, however, affords still more distilled again, is called rectified sjnril. It is 

spirit than wheat. Calculated, that a hundred gallons of malt or 

The practice with the distillere in Scotland corn wash will not produce above twenty of 

is, to use one part of malted with from four spirit, containing 60 parts of alcohol to 50 of 

to nine parts of unmalted grain. This mix- water : the same of cyder wash, 15 gallons ; 

ture yields an equal quantity of spirit^ and at and of melasses wash, 22 gallons. "[Die most 

a naucb cheaper rate than when the former spirituous wines of France, those of Langue- 

proportions are taken. doc, Guienne^ and Rousillon» yield, accoid-* 



ALC 



126 



ALC 



ing to Chaptal, from 20 to 25 gallons of ex- 
cellent brandy from 100 ; but those of Bur- 
gundy and Qiampagne much less. Brisk 
wines containing much carbonic add, from 
the fermentation having been stopped at an 
early period, yield the least spirit. 

llie spirit thus obtained ought to be co- 
lourless, and free from any disagreeable fla- 
your ; and in this state it is fittest for phar- 
maceutical purposes, or the extraction of tinc- 
tures. But for ordinary sale something more 
is required. The brandy of France, which is 
most in esteem here, though perfectly colour- 
less when first made, and often preserved so 
for use in that country, by being kept in glass 
or stone bottles, is put into new oak casks 
for exportation, whence it soon acquires an 
amber colour, a peculiar flavour, and some- 
thing like an uoctuosity of consistence. As 
it is not only prized for these qualities, but 
they are conunonly deemed essential to it, 
the English distiller imitates by design these 
accidental qualities. The most obvious and 
natural method of doing this, would be by 
impregnating a pure spirit with the extrac- 
tive, resinous, and colouring matter of oak 
shavings; but other modes have been oouf. 
trived. The dulcified spirit of nitre, as it is 
called, is commonly used to give the flavour ; 
and catechu, or burnt sugar, to impart the 
desired colour. A French writer has recom- 
mended three ounces and a half of finely 
powdered charcoal, and four ounces and a 
half of ground rice, to be digested for a fort- 
night in a quart of malt spirit. 

The finest gin is said to be made in Hol- 
land, from a spirit drawn from wheat mixed 
vrith a third or fourth part of malted barley, 
and twice rectified over juniper berries ; but 
in general rye meal is used instead of wheat. 
They pay so much regard to the water em- 
ployed, that many send vessels to fetch it on 
purpose from the Meuse; but all use the 
softest and clearest river water they can get. 
In England it is the common practice to add 
oil of turpentine, in the proportion of two 
ounces to ten gallons of raw spirit, with tliree 
faandfuls of bay salt, and drawn off till the 
feints begin to rise. 

But com or melasses spirit is flavoured 
likewise by a variety of aromadcs, with or 
without sugar, to please different palates : all 
of which are included under the general tech- 
nical term of compound* or cordials. 

Other articles have been employed, though 
not generally, for the fabrication of spirit, as 
carrots and potatoes ; and we are lately in- 
formed by Professor Proust, that from the 
fruit of the carob tree he has obtained good 
brandy, in the proportion of a pint from five 
pounds of the dried fruit 

It is stated, that the juice of the berries of 
the Morbus aucuparia (mountain-ash), are 
now used in the north of France for the 
production of spirit ; and the result is said to 



be equal to the finest distillation from fer- 
mented grapes for brandy. ^ Charooal is used 
in the second distillation to improve the 
flavour.- 

To obtain pure alcohol, diflbrent processes 
have been recommended. Boerhaave re- 
coDunended for thb purpose muriate of soda, 
added hot to the spirit But the subcarbo- 
nate of potash is preferable. About a third 
of the weight of the alcohol should be added 
to it in a glass vessel, well shaken, and then 
suffered to subside. The salt will be mois- 
tened by the water absorbed from the alco- 
hol ; which being decanted, more of the salt 
is to be added, and this is to be continued till 
the salt falls dry to the bottom of the vcwcl. 
The alcohol in this state will be reddened by 
a portion of the pure potash, vriiich it will 
hold in solution, from which it most be freed 
by distillation in a water bath. Dry muriate 
of lime may be substituted advantageously 
for the alkali. 

By encloang dilute aloriiol in a bladder, 
the water exudes, and the s^nrit is concen- 
trated. Soemmering says, that if we put 
alcohol of a moderate strength into an ox's 
bladder, or a calTs, coated with isinglass, and 
suspend it over a sand bath, in a few days 
the alcohol vriU lose one-fourth of its bulk, 
and be found quite free from water, or be- 
come absolute alcohoL^Gior. di Fitica, TiL 
239. 

As alcohol is much lighter than water, its 
specific gravity is adopted as the test of its 
purity. Lowits asserts that he has obtained 
it at 791, by adding as much alkaU as nearly 
to absorb the spirit ; but the temperature is 
not indicated. In the shops it is about 835 
or 840 : according to the London Collq^ it 
should be 825. 

It is by no means an easy undertaking to 
determine the strength or relative value of 
spiriti, even with sufficient accuracy for com- 
mercial purposes. 

The importance of this object also^ for the 
purposes of revenue, induced the British 
government to employ Sir Charles Blagden 
to institute a very minute accurate series of 
experiments, lliese may be considered as 
fundamental results; for which reason, I 
shall give a summary of their tabular re- 
sults, from the Philosophical IVansactiona 
for 1790. 

The precise specific gravity of the pure 
spirit employed was .82514; but to avoid an 
inconvenient frsction, it is taken, in con- 
structing the table of specific gravities, aa 
.825 only, a proportional deduction being 
made from all the other numbers. Thus the 
following table gives the true specific gravity, 
at the different degrees of heat, of a pure 
rectified spirit, the specific gravity of which 
at 60^ is .825, together vrith the specific 
gravities of different mixtures of it vrith 
water at those different temperatures. 



ALC 



187 



ALC 



Real Spedjie Gratilki at the differetU Temperatures* 



,w> 


The 
pore 
^irit 


100 

gzmittsof 

kpirit to 

5 gr. of 

water. 


100 

grains of 

spirit to 

10 gr. of 

water. 


100 
grains of 
spirit to 

^""^ 
water. 


100 
grains of 

spirit to 
Wgr. of 

water. 


100 
grains of 
spirit to 

Sgrof 
water. 


100 100 

grains of grains of 

spirit to spirit to 

a) gr. of 96 gr. of 

water, water. 


100 100 

grains of grains of 

spirit to spirit to 

40 gr. of 45 gr. of 

water. water. 


100 

grains of 

spirit to 

SOgr.of 

water. 


.83896 


.84995 


.85957 


.86825 


.87585 


.88282 


.88921 


.89511 


.90054 


.90558 


.91023 


3.5 


83672 


84769 


85729 


86587 


87357 


88059 


88701 


89294 


89839 


90345 


90811 


40 


83445 


84539 


85507 


86361 


87184 


87838 


88481 


89073 


89617 


90127 


90596 


45 


83214 


84310 


85277 


86131 


86905 


87613 


88255 


88849 


89396 


89909 


90380 


50 


82977 


84076 


85042 


85902 


86676 


87384 


88030 


88626 


89174 


oytJoTf 


90160 


55 


82736 


83834 


84802 


85664 


86441 


87150 


87796 


88393 


88945 


89458 


89933 


60 


82500 


83599 


84568 


85430 


86208 


86918 


87569 


88169 


88720 


89232 


89707 


65 


82262 


83362 


84334 


85193 


85976 


86686 


87337 


87938 


88490 


89006 


89479 


70 


82023 


83124 


84092 


84951 


85736 


86451 


87105 


87705 


88254 


88773 


89252 


75 


81780 


82878 


83851 


84710 


85496 


86212 


86864 


87466 


88018 


88538 


89018 


80 


81530 


82631 


83603 


84467 


85248 


85966 


86622 


87228 


87776 


88301 


88781 


85 


81291 


82396 


83371 


84243 


85036 


85757 


86411 


87021 


87590 


88120 


88609 


90 


81044 


82150 


83126 


84001 


84797 


85518 


86172 


86787 


87360 


87889 


88376 


95 


80794 


81900 


82877 


83753 


84550 


85272 


85928 


86542 


87114 


87654 


88146 


100 


80548 


81657 82639 


83513 84038 


85031 85688 


86302 > 86879 


87421 


87915 



HeaL 
30° 


100 
gndnsof 
spirit to 
!i5gr. of 
water. 


100 

grains of 

spirit to 

60gr. of 

water. 


100 

grains of 

qilritto 

65 gr. of 

water. 


100 

grains of 

spirit to i 

70gr.of 

water. 


100 

grains of 

spirit to 

75gr.of 

water. 


100 

grains of 

spirit to 

SOgr.of 

water. 


100 
grains of 
spirit to 
SSgr.of 
water. 


100 

grains of 

Kplrit to 

SOgr.of 

water. 


100 

grains of 

spirit to 

SSgr.of 

water. 


100 

grains of 

spirit to 

lOOgr.of 

water. 


.91449 


.91847 


.92217 


.92563 


.92889 


.93191 


.93474 


.93741 


.93991 


.94222 


35 


91241 


91640 


92009 


92355 


92680 


92986 


93274 


93541 


93790 


94025 


40 


91026 


91428 


91799 


92151 


92476 


92783 


93072 


93341 


93592 


93827 


45 


90812 


91211 


91584 


91937 


92264 


92570 


92859 


93131 


93382 


93621 


50 


90596 


90997 


91370 


91723 


92051 


92358 


92647 


92919 


93177 


93419 


55 


90367 


90768 


91144 


91502 


91837 


92145 


92436 


92707 


92963 


93208 


60 


90144 


90549 


90927 


91287 


91622 


91933 


92225 


92499 


92758 


93002 


65 


89920 


90328 


90707 


91066 


91400 


91715 


92010 


92283 


92546 


92794 


70 


89695 


90104 


JTvrUvTP 


90847 


91181 


91493 


91793 


92069 


92333 


92580 


75 


89464 


89872 


90252 


90617 


90952 


91270 


91569 


91849 


92111 


92364 


80 


89225 


89639 


90021 


90385 


90723 


91046 


91340 


91622 


91891 


92142 


85 


89043 


89460 


89843 


90209 


90558 


90882 


91186 


91465 


91729 


91969 


90 


88817 


89230 


89617 


89988 


90342 


90668 


90967 


91248 


91511 


91751 


95 


88588 


89003 


89390 


89763 


90119 


90U3 


90747 


91029 


91290 


91531 


100 


88357 


88769 


89158 


89536 


89689 


90215 


90522 


90805 


91066 91310 



Heat 



30° 

35 

40 

45 

50 

55 

60 

65 

70 

75 

80 



95 

grains of 

spirit to 

lUOgr.of 

water. 



90 
gxainsof _ 
spirit to |*pirit to 
lUOgr.of" 
water. 



QAAAT 

il Wm f 

94249 
94058 
93860 
93658 
93452 
93247 
93040 
92828 
92613 
92393 



85 
grains of 



lOOgr.of 
water. 



.94675 
94484 
94295 
94096 
93897 
93696 
93493 
93285 
93076 
92865 
92646 



80 

grains of 

spirit to 

lUUgr.of 

water. 



75 
grains of 



94920 
94734 
94547 
94348 
94149 
93948 
93749 
93546 
93337 
93132 
92917 



95173 
94988 
94802 
94605 
94414 
94213 
94018 
93822 
93616 
93413 
93201 



70 
grains of 



spirit to spirit to 



100gr.of 



95246 
95060 
94871 
94683 

94296 
94099 
93898 
93695 
93488 



lOUgr.of 
water. 



65 

grains of 

spirit to 

lOOgr.of 

water. 



.95681 
95502 
95328 
95143 
94958 
94767 
94579 
94388 
94193 
93989 
93785 



50 

grains of mrains of grains of 

spirit to 'spirit to Ispirltto 

lOOgr.of lOOgr.of lOOgr.of 

water. water, water. 



95772 
95602 
95423 
95243 
95057 
94876 

94500 
94301 
94102 



CO 55 

linsofmrainsof 
fit to <8piritto 



96209 
96048 
95879 
95705 
95534 
95357 
95181 
95000 
94813 
94623 
94431 



.96470 
96315 
96159 
95993 
95831 
95662 
95493 
95318 
95139 
94957 
94768 



.96719 
96579 
96434 
96280 
96126 
95966 
95804 
95635 
95469 
95292 
95111. 



ALC 



128 



ALC 



Heat 


45 

grains of 

spirit to 

100 gr.of 

water. 


40 

grains of 

spirit to 

lUOgr. of 

waier. 


S5 

grains of 

spirit to 

lU) gr.of 

water. 


90 

gfsiBsof 

spirit to 

100 gr.of 

water. 


25 

grains of 

spirit to 

100 gr.of 

water. 


80 15 

grains of grains of 

spirit to spirit to 

100 gr.of lOU gr.of 

water, water. 


10 

grains of 

spirit to 

100 gr.of 

water. 


5 

grains of 

spirit to 

100 gr.of 

water. 


30^ 


.96967 


.97200 


.97418 


.97635 


.97860 


.98108 '.98412 


.98804 


.99334 


35 


96840 


97086 


97319 


97556 


97801 


98076 98397 


98804 


W%jr§ri> 


40 


96706 


96967 


97220 


97472 


97737 


98033 


98373 


98795 


99345 


45 


96563 


96840 


97110 


97384 


97666 


97980 


98338 


98774 


99338 


50 


96420 


96708 


96995 


97284 


97589 


97920 


98293 


98745 


99316 


M 


96272 


96575 


96877 


97181 


97500 


97847 


98239 


98702 


99284 


60 


96122 


96437 


96752 


97074 


97410 


97771 


98176 


98654 


99244 


65 


95962 


96288 


96620 


96959 


97309 


97688 


98106 


98594 


99194 


70 


95602 


96143 


fUiAQA. 


96836 


97203 


97596 


98028 


98527 


99134 


75 


95638 


95987 


96344 


96708 


97086 


97495 


97943 


98454 


99066 


80 95467 


95826 


96192 


96568 


96963 


97385 97845 


98367 


98991 



From this table, wheD the specific gravity 
of any spirituous liquor is ascertained, it will 
be easy to find the quantity of rectified spirit 
of the above-mentioned standard, contained in 
any given quantity of it, either by weight or 
measure. 

Dr Blagden concludes with observing, that 
as the experiments were made with pure 
spirit and water, if any extraneous substances 
are contained in the liquor to be tried, the spe- 
cific gravity in the tables will not give exactly 
the proportions of water and spirit in it The 
substances likely to be found in spirituous li- 
quors, where no fraud is suspected, are essen- 
tial oils, sometimes eropyreumatic, mucilagi- 
nous or extractive matter, and perhaps some 
saccharine matter. The effect of these, in 
the course of trade, seems to be hardly such 
as would be worth the cognizance of the Ex- 
cise, nor could it easily be reduced to certain 
rules. Essetitial and empyreumatic oils are 
nearly of the same specific gravity as spirit, 
in general rather lighter, and therefore, not- 
withstanding the mutual penetration, will 
probably make little change in the specific 
gravity of any spirituous liquor in which they 
are dissolved. The other substances are all 
heavier than spirit; the specific gravity of 
common gum being 1.482, and of sugar 
1.606, according to the tables of M. Brisson. 
The effect of them, therefore, will be to male 
spirituous liquors appear less strong than they 
really are. 

Tlie strength of spirits is determined, ac- 
cording to the existing laws, by. Sikes's hy- 
drometer ; but as many dealers use Dicas's, 
I shall describe it here, and the former under 
Distillation. 

It consists of a light copper ball, terminat- 
ing below with a ballast bottom, and above 
vrith a thin stem, divided into ten parts. The 
upper extremity of the stem is pointed, to re- 
ceive the little brass poises, or discs, having 
each a hole in its centre. Tliese poises are 
numbered 0, 10, 20, 30, &c. up to 350, which 
is tlie lightest of the series. Tlic intermediate 



units are given by the subdivisions on tbe 
stem. A graduated ivory scale, with a slid- 
ing rule and thermometer, accompanies the 
hydrometer, to make the correction for tem- 
perature. The first thing in using this in- 
strument, is to plunge the thermometer into 
a glass cylinder containing the spirits to be 
tried, llie sliding rule has then tbe degree 
of temperature indicated, moved opposite to 
zero. The hydrometer is now placed in the 
liquid, and such a poise is put on as to sub- 
merge a portion of the stem. Tlie weight, 
added to the number on the stem, gives a 
sum, opposite to which on tlie scale we find 
a quantity by which the particular spirit may 
exceed or fall short of prooC Thus, if it 
mark 20 under proof, it signifies that every 
100 gallons of that spirit would require to 
have 20 gallons of water abstracted from it 
to bring it up to proof. If it mark 10 over 
proof, we learn that every 100 gallons con- 
tain too little water by 10 gallons. When the 
tbermometric degree of 60^ is put opposite 
to zero, then the weights and value of the spi- 
rits have the following relations on the scale. 

102.5 denotes 20 under proof 

122.0 10 

14a5 Proof 

167. 10 over proof 

19a 20 

221. 30 

251. 40 

284.5 50 

322.5 60 

350.5 Alcohol 

There is, besides, an upper line on 'the 
scale, which exhibits the reUtion of spirit to 
water reckoned unity. Thus, above 10 per 
cent over proof in the second line, we find 
in the upper line 8. From which we learn, 
that 8 of that spirit by bulk, will take 1 of 
water to bring it down to proof. At 60° 
Fahr. I find that 10 over proof on Dicas 
corresponds to specific gravity 0.9085 

34 over proof to 0. 9 169 

PWHjf, - 0.9218 



ALC 



180 



ALC 



Now» fay Gi!piD*ft tables tbis indicates a 
compound of 100 grains of alcohol 0.825^ 
and 85 grains of water. But by Lowits'a 
table in Creirs Annals, the above specific 
gravity corresponds to 46 alcohol of 0.791 
at the temperature of 68°, united to 52 of 
water, and cooled down to 60. Equal 
weights of that strong alcohol and water, 



give, at 60*^, a specific gravity of 0.9175i 
By the Act of Parliament of 1762, the spe^ 
cific gravity of proof was fixed at a916. It 
is at present to water as 12 to 13, or ^ 
0.923. See Ddhllation. 

For the following table of the quantity oC 
absolute alcohol, in spirits of diflferent den-» 
sities, we are indebted to Lowits. 



100 parts. 


Sp. gTBTitj. 


100 parti. 


Sp. gravity. 


100 parts. 


Spu gravity. 


Ale 


Wat. 


At«». 


At GO". 


Ale 


Wat 


At SB*. 


AtflO". 


Ala 


Wat 


AteB«. 


AtflO«. 


100 





a 791 


0.796 


66 


34 


0.877 


0.881 


32 


68 


0.952 


0.955 


99 


1 


0.794 


0.798 


65 


35 


0.880 


a883 


31 


69 


0.954 


0.957 


98 


2 


0.797 


0.801 


64 


36 


0.882 


a886 


30 


70 


0.956 


0.958 


97 


3 


0.800 


0.804 


63 


37 


0.885 


a889 


29 


71 


0.957 


0.960 


96 


4 


0.803 


0.807 


62 


38 


0.887 


a891 


28 


72 


0.959 


0.962 


95 


5 


0.805 


a809 


61 


39 


0.889 


0.893 


27 


73 


0.961 


0.963 


94 


6 


a808 


0.812 


60 


40 


0.892 


a896 


26 


74 


0.963 


0.965 


93 


7 


0.811 


a8l5 


59 


41 


0.894 


a898 


25 


75 


0.965 


0.967 


92 


8 


0.813 


0.817 


58 


42 


0.896 


0.900 


24 


76 


0.966 


0.968 


91 


9 


a816 


0.820 


57 


43 


0.899 


0.902 


23 


77 


0.968 


a 970 


90 


10 


0.818 


a822 


56 


44 


0.901 


0.904 


22 


78 


0.970 


0.972 


89 


11 


a821 


0.825 


55 


45 


b.903 


0.906 


21 


79 


0.971 


a97S 


88 


12 


0.823 


a827 


54 


46 


0.905 


0.908 


20 


80 


0.973 


0.974 


87 


13 


0.826 


0.830 


53 


47 


0.907 


0.910 


19 


81 


0.974 


0.975 


86 


14 


0.828 


0.832 


52 


48 


0.909 


0.912 


18 


82 


0.976 


0.977 


85 


15 


0.831 


a835 


51" 


49 


0.912 


0.915 


17 


83 


0.977 


0.978 


84 


16 


a834 


0.838 


50 


50 


0.914 


0.917 


16 


84 


a 978 


a979 


83 


17 


0.836 


a840 


49 


51 


0.917 


0.920 


15 


85 


0.980 


0.981 


82 


18 


a839 


0.843 


48 


52 


0.919 


a 922 


14 


86 


0.981 


0.982 


81 


19 


a842 


0.846 


47 


53 


0.921 


a924 


13 


87 


0.983 a984| 


80 


20 


0.844 


0.848 


46 


54 


0.923 


0.926 


12 


88 


0.985 


0.986 


79 


21 


0.847 


0.851 


45 


55 


0.925 


0.928 


11 


89 


p. 966 


0.987 


78 


22 


a849 


a853 


44 


56 


0.927 


0.930 


10 


90 


0.987 


0.988 


77 


23 


a851 


0.855 


43 


57 


0.930 


a933 


9 


91 


0.988 


0.989 


76 


24 


0.853 


a857 


42 


58 


a932 


0.935 


8 


92 


0.989 


0.990 


75 


25 


0.856 


0.860 


41 


59 


a934 


0.937 


7 


93 


0.991 


0.991 


74 


26 


aK59 


a863 


40 


60 


0.936 


0.939 


6 


94 


0.992 


0.992 


73 


27 


0.861 


0.865 


39 


61 


a938 


0.941 


5 


95 


0.994 




72 


28 


0.863 


0.867 


38 


62 


0.940 


0.943 


4 


96 


a995 




71 


29 


a866 


0.870 


37 


63 


a942 


0.945 


3 


97 


0.997 




70 


30 


0.868 


a872 


36 


64 


0.944 


0.947 


2 


98 


0.998 




69 


31 


0.870 


a874 


35 


65 


0.946 


0.949 


1 


99 


0.999 




68 


32 


0.872 


0.878 


34 


66 


0.948 


0.951 


100 


1.000 




67 


33 


0.875 


a879 


as 


67 


0.950 0.95311 









The most remarkable characteristic pro- 
perty of alcohol, is its solubility or combina- 
tion in all proportions vrith water ; a property 
possessed by no other combustible substance, 
except the acetic spirit obtained by distilling 
the dry acetates. When it is burnt in a 
chimney which communicates with the worm- 
pipe of a distilling apparatus, the product, 
which is condensed, is found to consist of 
water, which exceeds the spirit in weight 
about one-eighth part; or more accurately, 
100 parts of alcohol, by combustion, yield 
136 of water. If alcohol be burned in close 
vessels iritb vital air, the product is found to 
be water and carbonic add. Whence it is 



inferred, that alcohol conasts of hydrogen, 
united either to carbonic acid, or its addifi- 
able base ; and that the oxygen uniting on 
the one part with the hydrogen, forms water ; 
and on the other with the base of the carixK 
nic acid, forms that add. 

Some ingenious experiments have been re* 
cently made on this subject by M. de Saussure. 
Hie alcohol be used had, at 62.8^, a spedfic 
gravity of 0.8302 ; and by Richter's propor- 
tions, it consisted of 1&8 water, and86w2 of 
absolute alcohol. The vapour dT alcohol was 
made to traverse a narrow porcelain tube, ig-- 
nited, from which the products passed along- 
a glass tube about six f^ in length, refrige* 



ALC 



130 



ALC 



ntedbyicew A litde charcoal wis deponted 
in the porcelain, and a trace of oil in the 
glass tube. The resulting gas beuiffaDBlTwd 
in an exploding esdionKeler, with oxygen, 
was found to fesc^re itself into carbonic acid 
and water. Three volumes of oxygen dis- 
appeared for every two volumes of carbonic 
acid produced ; a proportion which obtains 
in the analysis by oxygenation of olefiant 
gas. Now, as nothing resulted but a com- 
bustible gas of this peculiar constitution, and 
condensed water equal to 44^4 of the origi- 
nal weight of the alcohol, we may conclude 
that vapour of water and olefiant gas are the 
sole constituents of alcohol. Subtracting 
the 13.8 per cent of water in the alcohol at 
the beginning of the experiment, the absolute 
alcohol of Richter will consist of 13.7 hydro- 
gen, 51.98 carbon, and 34.32 oxygen. Hence 
M. Gay; Lussac infers that alcohol, in va- 
pour, is composed of one volume olefiant gas, 
and one volume of the vapour of water, con- 
densed by chemical affinily into one volume. 
Hie sp. gr. of olefiant gas is 0.97804 
Of aqueous vapour is 0.62500 

Siim = 1.60304 
And alcoholic vapour is ^ 1.6133 
These numbers approach nearly to those 
which would result from. two prime equiva- 
lents of olefiant gas combined with one of 
vrater ; or, ultimately, three of hydrogen, two 
of carbon, and one of oxygen. 

Hie analytical experiments on alcohol were 
among the most satisfactory of any which I 
made on vegetable products, (see Analysis 
Vegetable) ; for in repeated verifications the 
results agreed within one or at most two- 
hundredths of a grain. Alcohol, specific gra- 
vity 0.812, afforded me in 100 parts, 47.85 
caibon, 12.24 hydrogen, and 39.91 oxygen ; 
or referring the last two to the composition of 
water, 44.9 of it, with 7.25 oxygen in excess. 
Such alcohol would therefore seem to consist 
nearly of 

Caibon, 3 atoms, 2.250 46.15 
Hydrogen, 6 0.625 12.82 

Oxygen, 2 2.000 40.03 

4.875 100.00 
Or of 3 atoms of olefiant gas = 2.625 

2 water s= 2.250; 

And in volumes, — 

3 vols, olefiant gas= 0.9722x3=2.9166 

4 aqueous vapours 0.625 X 4= 2.5000. 
Thus alcohol 0.812, by the above analysis, 
which I believe merits confidence, diiiers from 
M. Gay Lussac's view of absolute alcohol de- 
duced from the experiments of M. de Saus- 
sore^ in containing an additional volume of 
aqueous vapour. At the sp. gr. 0.814^ alco- 
hol would have exactly this atomic constitu- 
tion. If the oMidensation be equal to the 
ilrhole three volumes of olefiant gas, that is, if 
the seven vvhimes of constituent gases b^ 



come four of akoboL vapooTt we sfaaD fane the 

specific gnmtysetfaustrength=: 1.3722; tha 
additional v6lume of aqueous vapour produc- 
ing necessarily this abatement in the density. 
Messrs Dumas and BouUay have recently 
analyzed alcohol, and have given the follow- 
ing result:— 

Carbon, 52.37 

Hydrogen, 13.31 

Oxygen, 34.61 

100.00 

This constitution will agree with my ex- 
periments, when allowance is made for the 
water present in alcohol at 0.812 over abso- 
lute alcohoL 

A considerable number of the uses of this 
fluid as a menstruum will pass under our ob- 
servation in the various articles of this work. 
The mutual action between alcohol and acids 
produces a light, volatile, and inflammable 
substance, called ether. (See Etheb.) Pure 
alkalis unite with spirit of wine, and form al- 
kaline tinctures. Few of the neutral salts 
unite with this fluid, except such as contain 
ammonia. The carbonated fixed alkalis are 
not soluble in it. From the strong attraction 
which exists between alcohol and water, it 
unites with this last in saline solutions, and 
in most cases precipitates the salt. Hiis is a 
pleasing experiment, which never fails to sur- 
prise those who are unacquainted with che- 
mical effects. If, for example, a saturated 
solution of nitre in water be taken, and an 
equal quantity of strong spirit of wine be 
poured upon it, the mixture will constitute a 
weaker spirit^ which is incapable of holding 
the nitre in solution ; it therefore falls to the 
bottom instantly, in the form of minute crys- 
tahu 

The degrees of solubility of many neutral 
salts in alcohol have been ascertained by ex- 
periments made by Maoquer, of which an 
account is published in the Memoirs of the 
Turin Academy. The alcohol he employed 
was carefully freed from superabundant wa- 
ter by repeated rectifications, without addi- 
tion of any intermediate substance. The salts 
employed in his experiments were previously 
deprived of their water of crystallization by a 
careful drying. He poured into a matrass, 
upon each of the salts thus prepared, half an 
ounce of his alcohol, and set the matrass in a 
sand bath. When the spirit began to boil, 
he filtrated it while it was hot, and left it to 
cool, that he might observe the crystallizations 
which took place. He then evaporated the 
spirit, and weighed the saline residuums. He 
repeated these experiments a second time, with 
this difference, that instead of evaporating the 
spirit in which the salt had been digested, he 
set fire to it, in order to examine the pheno- 
mena which its flame might exhibit. The 
principal results of his experiments are sub- 
joinedt 



ALC 



131 



ALC 



efgramu 


SaUstolMein 
200 grains ofiptrU, 


4 


Nitrate of potash. 


5 



15 





108 

24 


Muriate of potash. 
Sulphate of soda. 
Nitrate of soda. 
Muriate of soda. 
Sulphate of ammonia, 
Nitrate of ammonia. 
Muriate of ammonia. 


288 


Nitrate of lime, 


288 
84 

204 

4 

36 


Muriate of lime^ 
Nitrate of silver. 
Muriate of mercury. 
Nitrate of iron. 
Muriate of iron. 


48 


Nitrate of copper. 


48 


Muriate of copper, 



Peculiar phenomena ofihejlame, 

( Flame larger, higher, more ardent, ydlow, 
i and luminous. 

Large, ardent, yellow, and luminous. 

Considerably red. 

Yellow, luminous, detonating. 

Larger, more ardent, and reddish. 

None. 

Whiter, more luminous. 

None. 

JLai|^, more luminous, red, and decrepi- 
tating. 

Like that of the calcareous nitres 

Nona 

Large, yellow, luminous, and decrepitating. 

Red and decrepitating. 

More whiter luminous, and sparkling. 
f More white, luminous, and green ; much 
< smoke. Hie saline residuum became 
C black and burnt 

Fine green, whiter and red fulgurafiona. 



. Macquer accompanies the relation of his 
experiments with many judicious reflections^ 
not easily capable of abridgment. 

The alcohol he employed in the above ex- 
periments had a specific gravity of 0.840. In 
analytical researches, alcohol affords frequent- 
ly a valuable agent for separating salts from 
each other. We shall therefore introduce the 
foUowiog additional table, derived chiefly 
from the experiments of Wenzel. 

100 parts of alcohol dissolve of— 

jTempm 



Kitnte of Cobalt, at 5^5^ 


100 parti 


Copper, 54.5 


100 


Alumina, 54.5 


100 


Lime, 


125 


Magnesia, 180.5 


290 


Muriate of Zinc, 54.5 


100 


Alumina, 51i.5 


100 


Muriate of Magnesia, 180.5 


547 


Iron, 180.5 


100 


Copper, 180.5 


100 


Acetate of Lead, 154.5 


100 


At the bailing point, 100 parts 


of alcohol 


dissolve of muriate of lime 


100 parts 


Nitrate of ammonia. 


89 


. Corrosive sublimate. 


sas 


Succinic add. 


74.0 


Acetate of soda. 


4a5 


Nitrate of silver. 


41.7 


Refined sugar. 


24.6 


Boracic acid, 


2ao 


^traleof soda. 


9.6 


Acetate of copper, - 


7.5 


Muriate of ammonia. 


7.1 


Supersrseniate of potash, 


a75 


Oxalate of potash, - 


2.92 


Nitrate of potash. 


2.08 


Muriate of potash, - 


2.08 


ArMniate of soda. 


1.58 


Arsenious acid. 


1.25 


Tartrate of potash, - 


a42 



It appears firom the experiments of Kirwan, 
that dried muriate of magnesia dissolves more 
abundantly in strong than in weak alcohoL 
100 parts of specific gravity 0.900, dissolve 
2L25; of 0.848, 2^75; of 0.834, 36.25; 
and of 0.817, 50 parts. The same holds to 
a more limited extent with acetate of lime ; 
2.4 grains being soluble in 100 of the first 
alcohol, and 4.88 in 100 of the last Tbe 
other salts which he- dried dissolved more 
sparingly in the stronger than in the weaker 
alcohoL The temperature of the spirit was 
generally 60^^. 

All deliquescent salts are soluble in alccK 
hoL Alcohol holding the strontitic salts in 
solution, gives a flame of a rich purple ; the 
cupreous salts and boracic add give a green; 
the soluble calcareous, a reddish ; the barylic, 
a yellowish. For the effect of other salts on 
the colour of the flame^ see a preceding table. 

The alcohol of 0.825 has been subjected to 
a cold of—- 91° without congealing. But 
Mr Hutton has given, in the Edinburgh En- 
cyclopaedia, artide Cold, an account of his 
having succeeded in solidifying it by a cold 
of— 110°. The alcohol he employed had a 
density of 0.798 at 60°. His process baa 
been kept secret See AOD (Sqlphuboub), 
for a mode of freezing alcohol by the evapo- 
ration of that acid in its liquefied state. The 
boiling point of alcohol of 0.825 is 176°. 
Alcohol of 0.810 boils at 17a5o. For the 
force of its vapour at different temperatures^ 
and its spedfic heat, see CalobiG^ and the 
Tables of Vapour at the end of the volume. 

When potassium and sodium are put in 
contact with the strongest alcohol, hydrogen 
18 evolved. When chlorine is made to pasa 
through alcohol in a Wolfe's apparatus, there 
is a mutual action. Water, an oily-looking 
substance, muriatic add, a little carbonic aoid, 
and carbonaceous matter, are the products* 



ALC 132 ALC 

This oily substance does not redden turnsole, principle ha?e been constructed at Glasgow 

though its analysis by beat shows it to con- for the West India dtstillersy and have been 

tain muriatic acidi It is whiter denser than found extremely advantageous. The Excise 

water, has a cooling taste analc^us to mint, laws do not permit their employment in the 

and a peculiar but not ethereous odour. It home trade. 

is very soluble in alcohol, but scarcely in wa- A very ingenious still on the above princi- 

ter. The strongest alkalis hardly operate pies has been recently invented by Mr J. J. 

on it. Saintmarc It has the aspect of a copper 

It was at one time maintained, that alco- tower, containing 9 or 10 stories, each apart- 

bol did not exist in wines, but was generated ment being divided from the one below by s 

and evolved by the heat of distillation. On horizontal partition or floor, pierced with 

this sulject M. Gay Lussac made some de- openings or vertical pipes, admirably fitted 

dsive experiments. He agitated wine with for transferring to the highest stage, a very 

litharge in fine powder, till the liquid became fine concentrated spirit in an uninterrupted 

as limpid as water, and then saturated it with operation. The lowest floor alone is exposed 

subcarbonate of potash. The alcohol imme- to the naked fire, and the upper ones have 

diately separated, and floated on the top. He their contents heated by the steam which it 

distilled another portion of wine in vacuo, at causes to ascend. The apparatus has an ap- 

59^ Fahr. a temperature considerably below pearance of complication, but I should think 

that of fermentation. Alcohol came over, it quite simple and BatisfiM;tory in its per- 

Mr Brande proved the same position by sa- ibrmance. It has been made the subject of 

turating wine with subacetate of lead, and a patent, 

adding potash. If sulphur in sublimation meet with the 

MM. Adam and Duportal have subsdtut- vapour of alcohol, a very small portion corn- 
ed for the redistillations used in converting bines with it, which communicates a hydro* 
wine or beer into alcohol, a single process of sulphurous smell to the fluid. Hie increased 
l^reat el^ance. From the capital of the stiU surface of the two substances appears to &- 
a tube is led into « large copper recipient vour the combination. It had been suppos* 
Tliis is joined by a second tube to a second ed, that this was the only way in which they 
recipient, and so on through a series of four could be united ; but M. Favre has lately 
vessels, arranged like a Woolfe*s apparatus, asserted, that having digested two drams ot 
The last vessel communicates with ihe worm flowers of sulphur in an ounce of alcohol, 
of the first refrigeratory. This, the body of over a gentle fire, not suflident to make it 
the still, and the tworedpients nearest it, are boil, for twelve hours, he obtained a solution 
charged with the wine or fermented liquor4 that gave twenty-three grains of precipitate. 
"When ebullition takes place in the still, the A similar mixture left to stand for a month 
vapour issuing from it communicates soon in a place exposed to the solar rays, afforded 
the boiling temperature to the liquor in the sixteen grains of predpitate ; and another, 
two recipients. From these the volatilized from which the light was excluded, gave 
alcohol will rise and pass into the third ves- thirteen grains. If alcohol be boiled with 
sel, which is empty. After communicating one>fourUi of its weight of sulphur for an 
a certain heat to it, a portion of the finer or hour, and filtered hot, a small quantity of 
less condensable spirit will pass into the minute crystals will be deposited on cooling; 
fourth, and thence, in a little, into the worm and the clear fluid will assume an opaline 
of the first refrigeratory. The wine round hue on bdng diluted with an equal quantity 
the worm will likewise acquire heat, but more of water, in which state it will pass the filter, 
slowly. The vapour that in that event may nor will any sediment be deposited for seve- 
pass uncondensed through the first worm, is ral hours. The alcohol used in the last men- 
conducted into a second, surrounded with tioned experiment did not exceed .840. 
cold water. Whenever the still is worked ofl^ Phosphorus is sparingly soluble in alcohol, 
it is replenished by s stopcock from the near- but in greater quantity by heat than in cold. 
est redpient, which, in its turn, is filled from The addition of water to this solution affords 
the second, and the second from the first an opaque milky fluid, which gradually . e- 
worm tub» It is evident, from this arrange- comes clear by the subsidence of the phos- 
ment, that by keeping the 3d and 4th red- phorus. 

pients at a certain temperature, we may cause Earths seem to have scarcely any action 

alcohol, of any degree of lightness, to form upon alcohol. Quicklime, however, produces 

directly at the xemote extremity of the appa- some alteration in this fluid, by changing its 

latus. The utmost economy of fuel and flavour, and rendering it of a yellow colour, 

tame is also secured, and a better flavoured A small portion is probably taken up. 

spirit is obtained. The arrOre gout of bad Soaps are dissolved with great facility in 

spuit can scarcely be destroyed by infusion alcohol, with which they combine more rea- 

with charcoal and redistillation. In this mode dily than with water. None of the metals, 

of operating^ the taste and smell are excellent or their oxides, are acted upon by t is fluid, 

from the first Several stills on the above Resins, essential oils, camphor, bitumen, and 



ALC 



133 



ALI 



various other substances^ are dissolved with 
great facility in alcohol, from which they 
may be precipitated by the addition of water. 
¥Vom its property of dissolving resins, it 
becomes the menstruum of one class of var- 
Dishes. See Varnish. 

Camphor is not only extremely soluble in 
alcohol, but assists the solution of resins in it.' 
Fixed oils, when rendered drying by metallic 
oxides, are soluble in it, as well as when 
combined with alkalis. 

Wax, spermaceti, biliary calculi, urea, and 
all the animal substances of a resinous nature, 
are soluble in alcohol ; but it curdles milk, 
coagtthues albumen, and hardens the muscu- 
lar fibre and coagulum of the blood. 

The uses of alcohol are various. As a sol- 
rent of resinous substances and essential oils, 
it is employed both in pharmacy and by the 
perfumer. When dOuted with an equal quan- 
tity of water, constituting what is caUed proof 
spirit, it is used for extracting tinctures from 
Testable and other substances ; the alcohol 
dissolving the resinous parts, and the water 
the gummy. From giving a steady beat 
without smoke when burnt in a lamp, it was 
formerly much employed to keep water boil- 
ing on the tea-table. In thermometers, for 
measuring great degrees of cold, it is prefer- 
able to mercury. It is in common use for 
preserving many anatomical preparations, and 
certain subjects of natural history ; but to 
some it is injurious, Uie molluscae for in- 
stance, the calcareous covering of which it in 
time corrodes. It is of considerable use too 
in chemical analysis, as . appears under the 
difTerent articles to which it is applicable. 

From the great expansive power of alco- 
hol, it has been made a question, whether it 
might not be applied with advantage in the 
vrorking of steam-engines. From a series of 
experiments made by Betancourt, it appears, 
that the steam of alcohol has, in aU cases of 
equal temperature, more than double the 
force of that of water ; and that the steam of 
alcohol at 174><^ K is equal to that of water 
at 21^. Tlius tliere is a considerable dimi- 
nution of tibe consumption of fuel ; and where 
this is so expensive as to be an object of great 
importance, by contriving the machinery so 
as to prevent the alcohol from being lost, it 
may possibly at some future time be used 
with advantage, if some other fluid of great 
expansive power, and inferior price, be not 
found more economical. 

In my experiments on vapours, I found 
that the latent heat of that of alcohol is less 
than one^half that of water ; for which rea- 
son the former would serve well for impell- 
ing the pistons of steam-engines, were it not 
to act on the metals, which has been sur- 
mised. 

It was observed at the beginning of this 
article, that alcohol might be decomposed by 
transroiaaion through a red-hot tube: it is also 



decomposable by the strong adds, and thus 
affords that remarkable product, E^heb, and 
Oleum Vinl 

ALE. See Beer. 

ALBEMIC, or STILL. This part of 
chemical apparatus, used for distilling or se<* 
parating volatile products, by first raising 
them by beat, and then condensing them into 
the liquid state by cold, is of extensive use in 
a variety of operations. It is described un- 
der the article Laboratory. 

ALEM BROTH SALT. Corrosive mu- 
riate of mercury is rendered much more solu* 
ble in water, by the addition of muriate of 
ammonia. From this solution crystals are 
separated by cooling, which were odled sal- 
alerobroth by the earlier chemists, and appear 
to consist of ammonia, muriatic acid, and 
mercury. 

ALGAROTH (POWDER OF). Among 
the numerous preparations which the alche- 
mical researches into the nature of antimony 
have aflfbrded, the powder of algaroth is one. 
When butter of antimony is thrown into 
water, the greater part of the metallic oxide 
falls down in the form of a white powder, 
which is the powder of algaroth. It is vio*- 
lently purgative and emetic in small doses of 
three or four grains. See Amtoiony. 

ALIMENTARY SUBSTANCES. The 
chemical relations of tiiese substances have 
lately formed the subject of an elaborate me- 
moir by Dr Flrout. His first object was, to 
devise, if possible, an unexceptionable mode 
of determining the proportions of the three 
or four principles, which, with few excep- 
tions, form organic bodies ; and after nume- 
rous trials, be adopted a method, founded 
upon the following well known principles. 
Wlien an oi^nic product, containing three 
elements, hydrogen, carbon, and oxygen, is 
burnt in oxygen gas, one of three things 
must happen :— 1. The original bulk of oxy- 
gen gas may remain the same ; in which case 
the hydrogen and oxygen in the substance 
must exist in it in the same proportions in 
which they exist in water ; or, 2. The origi- 
nal bulk of the oxygen may be increased; in 
which case the oxygen roust exist in the sub- 
stance in a greater proportion than it exists 
in water ; or, 3. The original bulk of the 
oxygen gas may be diminished ; in which 
case the hydrogen must predominate. Hence 
it is obvious, that in the first of these cases 
the composition of a substance may be de- 
termined, by simply ascertaining tiie quantity 
of carbonic acid gas yielded by a known 
quantity of it ; while in the other two, the 
same can be readily ascertained by mean's of 
the same data, and by noting the excess or 
diminution of the original bulk of the oxy- 
gen gas employed. 

Dr Prout*s apparatus consists of two in- 
verted glass syphons, which act the part of 
gasometeis: these are connected, when re- 



AM 



134^ 



ALK 



quired» by a mudl green glass tube^ in which 
the substance is to be decomposed and burnt. 
Tlie syphons are very carefully graduated, so 
that the quantity of gas in them can be aocu- 
tatdy estimated ; and are supplied with cocks 
both above and below, so that they can be 
filled with mercury, the mercury drawn off 
and gas introduced, the gas transferred 
through the green glass tube, or the contents 
retained in an undisturbed states with the 
utmost readiness and ease. Hie substance 
to be decomposed may be put into a platina 
tray, and introduced alone into the green 
glaos tube» axid being there heated by a spirit 
lamp, be burnt in the gas passing over it; or 
it may be mixed with pure siliceous sand ; 
or, what is most generally preferable^ be 
mixed with peroxide of copper, which is al- 
ways left, in consequence of the excess of 
oxygen gas used, in the state in which it was 
introduced. After the experiment, the volume 
of gas is easily corrected for pressure, and, if 
necessary, for temperature, and the carbonic 
add ascertained by the removal and analysis 
of a portion. No correction is required for 
moisture, the gas always being used saturated 
with water. 

Dr Pirout considers the principal alimentary 
substances as reducible to three great classes, 
the saecharinef the oi/y, and the albuminous ; 
and his paper relates to the first of these. 
This, with certain exceptions, includes the 
substances in which, according to MM. Gay 
Lusaac and Thenard, the oxygen and hydro- 
gen are in the same proportion as in water. 
Such substances are principally derived from 
the vegetable kingdom; and being at the 
same time a/mMiiiory, Dr Prout uses the 
terms taccharine jfrindpU and vegeiabie dU^ 
ment as synonymous. 

Tlie following tables show some of Dr 
Ftrout*s results with several substances, ex- 
treme care having been taken in every case 
to obtain the bodies pure, and new processes 
were often resorted to for that purpose. 

SUGAB. 
Carbon. Water. 

Pure sugar candy, 42.85 57. 1 5 

Impure sugar can- 
dy, - 41.5 to 42.5 5&5 to 57.5 

East India sugar 
candy, - 41.9 5a 1 

English refined 
sugar, 41.5 to 42.5 5a5 to 57.5 

Maple sugar, 42.1 57.9 

Beet-root sugar, 42.1 57.9 

East India moist 
sugar, - 40.88 59.12 

Sugar of diabetic 
urine, - 36 to 40? 64 to 60? 

Sugar of Nar- 
bonne honey, 36.36 63.63 

Sugar fromstarcb, 36.2 63.8 



AlCYLACEOUS PBINGIFLE8. 

Carb, WaU 
Fine wheat starch, 37.5 62.5 

dried, («) 42.8 57.2 

highly dried,(«) 44.0 56.0 

Arrowroot, - - 36.4 6a6 

dried,(3) - 42.8 57.8 

-«— — * hi^ly dried, 44.4 55.6 

(<) Was dried between 200<> and 212o for 
twenty hours, lost 12.5 per cent. 

n) Part of the former, dried between 300^ 
ana 350^, for six hours, lost 2.3 per cent. 

(^) Dried as (*), lost 15 per cent. 

(4) Ptot of the last, heated to 212<' for six 
hours longer, lost 3.2 per cent more. 

LiGNiN OR Woody Fibre. 
Obtained by rasping wood, and then pul- 
verizing it in a mortar ; boiling the impal- 
pable powder in water till nothing more waa 
removed; then in alcohol; again in vniter, 
and dried in the air till they ceased to lose 
weight 

Carb, Wat, 
From box, - - 42.7 57.3 

dried,(») - 50 50 

From willow, - 42.6 57.4 

dried,(0 - 49.8 50.2 

(0 Dried at 212<^ for six hours, afterwaida 
between 300^ and 3500 for six houn. xi^t 
from box lost 14.6, that from vrillow 14.4 
per cent 

Curb. Wat. 

Acetic acid, - 47.05 52.95 
Sugar of milk, - 40.00 60 
Manna sugar, - 3a7 61.3 

Gum-arabic - 36.3 6a7 

dried, (>) 41.4 5a6 

(') Dried between 2009 and 212^^ for 20 
hours, lost 12.4 per cent. The same gum 
further heated to between 300^ and 350^ for 
six hours, lost only 2.6 per cent, and had be- 
come deep brown. 



Vegetable adds. 


Carbon. 


Water. 


Oxygen. 


Oxalic acid. 


19.04 


42.85 


38.11 


Citric add. 


34.28 


42.85 


22.87 


Tartaric add. 


32.00 


36.00 


32.00 


Malic add, 


40.68 


45.76 


13.56 


Sacburtic add. 


3a33 


44w44 


22.22 



ALIZARINE. See Madder. 

ALK A HEST. The pretended universal 
solvent or menstruum of the ancient chemists. 
Kunckel has very well shown the absurdity 
of searching for a universal solvent, by ask- 
ing, ** If it dissolve all substances, in what 
vessels can it be contained ?*' 

ALKALESCENT. Any substance in 
which alkaline properties are banning to be 
developed, or to predominate^ is termed alka- 
lescent The only alkali usually observed to 
be produced by spontaneous decomposition is 
ammonia; and from their tendency to pro- 
duce this, some spedes of v^^etables, parti- 
cularly the cruciform, are styled aLkalescent, . 



ALK laS ALK 

n an nme miiiMl lubstancea. See Fee- morphiay strycbnia, qiiiai% ciiidioiiiii% «m| 
I&BNTATION (Poteid). pcrfasps flOBM otfaor truly vegetable alkalii. 



ALKALI. A term deriTed from kah, Tboe are called by the German chemists, al- 
the Arabic name of a plant, tnm ifae aahes kaloids. (See^EGETABLE Kingdom.) Hie 



of wbich one apedea of alkaline substance order of vegetable alkalis maj be as nmne- 

can be eitracted. Alkalis may be deSned, rous as that of vegetable adds. The earths, 

those bodies which combine with adds, so as lime, baryta, and strontia, were enrolled 

to neutraliae or impair their activity, and pro^ among the alkalis by Fourcroy ; but they 

duoe salts. Acidity and alkalinity are there- have been kept apart by other systematic 

fore two correlative terms of one spedes of writen» and are called alkaline earths. 
combination. When Lavoisier introduced Besides neutralising addity, and thereby 

oxygen as the acidifying prindple^ Morveau giving birth to salts, the first four alkalis hav^ 

proposed hydrogen as the alkalifying prind- the following properties :— 
ple^ from its bong a constituent of volatile l<l» They change the purple colour of many 

alkali or ammonia. But the splendid dis- vegetables to a green, the reds to a purple, 

oovery by Sir H. Davy, of the metallic bases and the yellows to a brown. If the purple 

of potash and soda, and of thdr conversion have been reddened by add, alkalis restore 

into alkalis by combination with oxygen, has the purple. 

banished for ever that hypothetical concdt. 2fi^ They possess this power on vegetable 

It is the mode in which tlie constituents are colours after bang saturated with carbonic 

combined, rather than the nature of tibe con- add, by which criterion they are distinguish- 

stituents themselves, which gives rise to the able from the alkaline earths. 
add or alkaline condition. Some metals, Sd, They have an acrid and urinous taste, 
combined with oxygen, in one proportion pro- 4f A, They are powerful solvents or corro- 

dnce a body possessed of alkaline properties^ sives of animal matter ; with which, as well 

in another proportion of add properties. And u with fat of oils in general, they combine^ 

on die other hand, ammonia and prussic add so as to produce neutrality. 
prove that both the alkaline and add oondi- ^A, They are decomposed, or volatilised, 

tions can exist independent of oxygen. Tbeee at a strong red heat 

obaervations, by generalising our notions of 6M, They combine with water in every 

adds and alkaUs, have rendered the defini- proportion, and also largely irith alcohoL 
tions of them very imperfect The difficulty 7M, They continue to be soluble in water 

of tiadng a limit between the adds and al- when neutralised with carbonic add ; while 

kalis is still increased, when we find a body the alkaline earths thus become insoluble, 
sometimes perfbrming the functions of an It is needless to detail at length Dr Mur- 

acid, sometimes of an alkali. Nor can we ray*8 speculations on alkalinity. They seem 

diminish this difficulty by having recourse to to flow from a partial view of chemical phe- 

tbe beautiful law discovered by Sir H. Davy, nomena. According to him, either oxygen 

that oxygen and adds go to the positive pole, or hydrogen may generate alkalinity, but th« 

and hydrogen, alkalis, and inflammable bases, combination of both prindples is necessary to 

to the n^ative pole. We cannot in fact give give this condition its utmost energy. " Ilius 

the name of add to all the bodies which go the class of alkalis will exhibit the same rela- 

to the first of these poles, and that of alkali to tions as the class of adds. Some are com- 

those that go to the second ; and if we wish pounds of a base with oxygen ; such are the 

to define the alkalis, by bringing into view greater number of the metallic oxides, and 

thdr dectric energy, it would be necessary probably of the earths. Ammonia is a conK 

to compare them with the electric energy pound of a base with hydrogen. Potash, 

which is opposite to them. Thus we are al- soda, baryta, strontia, and probably lime, ara 

ways reduced to define alkalinity by the pro- compounds of bases with oxygen and hydro-i 

perty which it has of saturating addity, be- gen ; and these last, like the analogous order 

cause alkalinity and addity are two correla- among the adds, possess the highest power.*' 

Uve and inseparable terms. M. Gay Lussac Now, surely, perfectly dry and caustic bary ta» 

conodves the alkalinity which the metallic ox- lime^ and strontia, as well as the dry potash 

ides eigoy, to be the result of two opposite pro- and soda obtained by Gay Lussac and Th^ 

perties, tiie alkalifying property of the metal, nard, are not inferior in alkaline power to tha 

and the acidifying of oxygen, modified both same bodies after they are slacked or com- 

by the combination and by the proportions. bined with water. 100 parts of lime desti-. 

The alkalis may be arranged into three tute of hydrogen, that is, pure oxide of caU 

dasses:— l<r, Those which consist of a me- dum, neutralise 78 parts of carbonic add. 

tallic basis combined with oxygen. These But 132 parts of Dr Murray's j|rofi^«<flimc^ 

are three in number, potash, soda, and lithia. that is the hydrate, are required to produce 

2df That which contains no oxygen, vis. am- the same alkaline effect. If we ignite nitrate 

monia. 3d, lliose containing oxygen, by- of baryta, we obtain, as is well known, a per- 

drogen, and carbon. In this daas we have fectly dry baryta, or protoxide of barium ; 

aconite, bnida, datura, ddphia, hyotdama, but if we ignite ctystallized barytsi we obtain 



ALK Id6 ALL 

the fuune alludine etrth combined with a prime tinged with it, and applied on warm maible^ 
equiTalent €f water. Tliese two different ttaios it of a flesh colour, which sinks deep, 
states of baryta were demonstrated by M. into the stone ; as the spirituous tincture 
Berthollet, in an eicellent paper published gives it a deep red stain, 
in the 2d volume of the Memoires d* Arcueil, As the colour of this root is confined to 
so far back as 1809. *' The first baryta,*' the baric, and the small roots have more bark 
(that from crystallized baryta), says he, ** pre- in proportion to their bulk than the great 
sents all the characters of a combination : it ones, these also afford most colour. 
is engaged with a substance which diminithes ALLAGITE. A carbo-silicate of man- 
its action on other bodies, which renders it ganese. 

more fusible^ and which gives it by fusion the ALL ANITE. A mineral first recognised 
appearance of glass. 'Diis substance is no- as a distinct species by Mr Allan, of £din- 
tfaing else than water; but in fact, by adding burgh, to whose accurate knowledge and 
a little water to the second baryta (that from splendid collection, the science of miners- 
ignited nitrate), and by urging it at the fire, logy has been so much indebted in Scotland, 
we give it the properties of the first" Page Its analysis and description, by Dr Tliom- 
47. 100 parts of baryta void of hydrogen, son, were published in the 6th volume of the 
or dry baryta, neutralize 28^ of dry cartwnic Edinburgh PhiL IVans. M. Giesecke found 
add. Whereas 111^ parts of the hydrate, it in a granite rock in West Greenland. It 
or what Dr Murray has styled the most ener- is massive, and of a brownish-black colour, 
getic, are required to produce the same effect. External lustre^ dull ; intemaU shining and 
In ftct, it is not hydrogen which combines resinous ; fiacture small conchoidal-^opaque 
with the pure barytic earth, but hydrogen ^-greenish-grey streak scratc hes glass and 
and oxygen in the state of water. The proof homblende----brittle ; spec. grav. 3.5 to 4i.O ; 
of this is, that when cart>onic acid and that froths and melts imperfectly before the blow- 
hydrate unite, the exact quantity of water is pipe into a black scoria. It consists, in 100 
disengaged. The protoxide of barium, or parts, of silica 35.4s oxide of cerium 33.1^ 
pure baoTta, has never been combined with oxide c€ iron 25.4, lime 9.2, alumina 4. 1, 
hydrogen by any chemist and moisture 4.0. It has been also found 
ALKALI (MINERAL or FOSSIL), crystallized in four, six, or eight-sided prisms. 
An old name of Soda. It closely resembles g^olinite, but may be 
ALKALI (PHLOGISTICATED, or distinguished from the thin fragments of the 
PRUSSIAN). When a fixed alkali is ig- latter, being translucent on the edges, and of 
nited with bullock*s blood, or other animal a fine green colour, whereas those of the for- 
substances, and lixiviated, it is found to be mer are commonly opaque and of a yellowish- 
in a great measure saturated with the prussic brown. The ores of cerium, analyzed by Ber- 
add : From the theories formeriy adopted re- zelius under the name (^ cerin, approach very 
Bpecting this combination, it was distinguish- closely in their composition to allanite. 
ed by the name of phlogisticated alkalL See ALLOCHROITE. A massive opaque 
Aqd (Prussic). mineral, of a greyish, yellowish, or reddish 
ALKALI (VOLATILE). See Am- colour. Quartz scratches it, but it strikes fire 
MONIA. with steel. It has externally a glistening, 
ALKALIMETER. The name first given and internally a glimmering lustre. Its 
by M. Descroizilles to an instrument or mea- fracture is uneven, and its fragments are 
sure of bis graduation, for determining the translucent on the edges : sp. gr. 3.5 to 3.6. 
quantity of idkali in commercial potash and It melts before the blowpipe into a black 
soda, by tlie quantity of dilute sulphuric acid opaque enamel. Vauquelin's analysis is the 
of a known strength which a certain weight following : silica 35, lime 30.5, oxide of iron 
of them could neutralize. 17, alumina 8, carbonate of lime 6, oxide of 
ALKANET. The alkanet plant is a manganese 3.5. M. Brogniart says it is ab- 
klnd of bugjoss, which is a native of the solutely infusible without addition, and that 
warmer parts of Europe, and cultivated in it requires a flux, as phosphate of soda or am- 
some of our gardens. Ibe greatest quanti- monia. With these it passes through a beau- 
ties are raised in Germany and France, par- tiful gradation of colours. It is covered at 
ticularly about Montpelier, whence we are first with a species of enamel, which becomes 
chiefly supplied with the roots. These are on cooling riKidish-yeUow, then greenish, and 
of a superior quality to such as are raised in lastly of a dirty yellowish-white. He repre- 
England. This root imparts an elegant deep sents it as pretty difficult to break. It was 
red colour to pure alcohol, to oils, to wax, found by M. Dandrada in the iron mine of 
and to all unctuous substances. The aqueous Virums, near Dremmen in Norway. It is 
tincture is of a dull brownish colour ; as is accompanied by carbonate of lime, protoxide 
likewise the spirituous tincture when inspis- of iron, and sometimes brown garnets, 
sated to the consistence of an extract The ALLOPHANE. A mineral of a blue, 
principal use of alkanet root is, that of colour- and sometimes a green or brown colour, which 
ing oils, unguents, and lip-salves. Wax occurs massive^ or in imitative shapes. Lus-. 



ALL 



137 



ALL 



in vitreous ; fiMcture imperfectly ooncboicbl ; 
tnmsparent or tmislucent on the edges. Mo- 
derately hard, but very brittle. Sp. gr. L89. 
Composition, silica 21.92, alumina 32.2, 
lime 0.73^ sulphate of lime 0.52, carbonate 
of copper 3.06, hydrate of iron 0.27, water 
41.3.— 5i(rDin€ytfr. It gelatinises in adds. 
It is found in a bed of iron-shot limestone in 
greywacke slatc^ in the forest of Thuringia. 
It was called Riemannite. 

ALLAY, or ALLOY. Where any pre- 
dotts metal is mixed with another of less 
Tahie^ the assayers call the latter the alloy, 
and do not in general consider it in any other 
point of view than as debasing or diminishing 
the value of the precious metal. Philosophi- 
cal chemists have availed themselves of this 
term to distinguish all metallic compounds in 
generaL Thus brass is called an alloy of cop- 
per and zinc ; bell-metal, an alloy of copper 
and tin. 

Alloys are not, as far as we know, definite- 
ly regulated like oxides in the proportions of 
their component parts. 100 parts of mercury 
will combine with 4 or 8 parts of oxygen, to 
form two distinct oxides, the black and the 
red ; but with no greater, less, or interme* 
diate proportions. But 1 00 parts of mercury 
will unite with 1, 2, 3, or with any quantity 
np to 100 or 1000, of tin or lead. The al- 
loy% have the closest relations in their physi- 
cal properties with the metals. They are all 
solid at the iemperature of the atmosphere, 
except some amalgams : they possess metallic 
lustre, even when reduced to a coarse pow- 
der ; are completely opaque, and more or less 
dense, according to the metals which compose 
tbem ; are excellent conductors of electridty ; 
crystallize more or less perfectly : some are 
brittle^ others ductile and malleable; some 
have a peculiar odour ; several are very sono- 
rous and elastic. When an alloy consists of 
metals differently fusible^ it is usually mal- 
leable while cold, but brittle while hot ; as is 
exemplified in brass. . 

The density of an alloy is sometimes great- 
er, sometimes less, than the mean density of 
its components, showing that, at the instant 
of their union, a diminution or augmentation 
of volume takes place. Hie relatiqn between 
the expansion of the separate metals and that 
of their alloys, has been investigated only in 
a very few cases. Alloys containing a vola- 
tile metal are decomposed, in whole or in 
part, at a strong heat. This happens vrith 
those of arsenic, mercury, tellurium, and zinc 
Those that consist of two dififerently fusible 
metals, may often be decomposed by expos- 
ing them to a temperature capable of melting 
cmly one of them. This operation is called 
eliquation. It is practised on the great scale 
to extract silver from copper. The argenti- 
ferous copper is melted with 3§ times its 
weight of lead ; and the triple alloy is expos- 
ed to a bofiicient heat The lead carries off* 



the silver in its fusion, and leaves the copper^ 
under the form of a spongy lump. Hie sU- 
ver is afterwards recovered from the lead by 
another operation. 

Some alloys oxidize more readily by heat 
and air, than when the metals are separately 
treated. Thus 3 of lead, and 1 of tin, at a 
dull red, bum visibly, and are almost instant- 
ly oxidized. Each by itself, in the same dr- 
cumstances, would oxidize slowly, and with- 
out the disengagement of light 

Tlie formation of an alloy must be regu- 
lated by the nature of the particular metals, 
to whidi therefore we refer. 

The degree of aflinity between metals, may 
be in some measure estimated by the greater 
or less fadlity with which, when of difl^erent 
degrees of fusibility or volatility, they unite, 
or with which they can after union be sepa- 
rated by heat llie greater or less tendency 
to separate into different proportional alloys, 
by long continued fusion, may also give some 
information on this subject Mr Hatcbett 
remarked, in his admirable researches on me- 
tallic alloys, that gold made standard with 
the usual precautions by silver, copper, lead, 
antimony, &c. and then cast into vertical bars, 
was by no means an uniform compound ; but 
that the top of the bar, corresponding to the 
metal at the bottom of the crudble, contain- 
ed the larger proportion of gold. Hence, for 
thorough combination, two red-hot orudbles 
should be employed ; and the liquefied metals 
should be alternately poured from the one 
into the other. And to prevent unnecessary 
oxidizement by exposure to air, the crudbles 
should contain, besides the metal, a mixture 
of common salt and pounded charcoaL The 
melted alloy should also be occasionally stir- 
red up with a rod of pottery. 

The most direct evidence of a chemical 
change baring taken place in the two metals 
by combination, is when the alloy melts at a 
much lower temperature than the fusing 
points of its components. Iron, which is 
nearly infusible, when alloyed with gold, ac- 
quires almost the fusibility of this metal. Tin 
and lead form solder, an alloy more fusible 
than either of its components ; but the triple 
compound of tin, lead, and bismuth, is most 
remarkable on this account The analogy is 
here strong, with the increase of solubility 
which salts acquire by mixture, as is exem- 
plified in the uncrystallizable residue of saline 
solutions, or mother waters, as they are call- 
ed. Sometimes two metals will not directly 
unite, which yet, by the intervention of a 
third, are made to combine. This happens 
with mercury and iron, as has been shown 
by Messrs Aikin, who effected this difiScult 
amalgamation by preriously uniting the inm 
to tin or zinc. 

The tenacity of alloys is generally, though 
not always, inferior to the mean of the sepa- 
rate metals. One part of lead will destroy 



ALL 



138 



ALM 



the Gompactncfls and tenacity of a tfaounnd 
of gold. Bran made with a nnall propor- 
tion of zioc, is more ductile than copper it- 
self; but when one^third of sine enten into 
its composition, it becomes brittle. 

In common cases^ the specific gravity af- 
fords a good criterion whereby to judge of 
tibe proportion in an alloy, conasting of two 
metak of different densities. But a very fal- 
lacious rule has been given in some respec- 
table works, for comparing the specific gravi- 
ty that should result from given quantities 
of two metals of known densities allojred to- 
gether, supposing no chemical poietration or 
expansion of volume to take place. Thus it 
baa been taught, that if gold and copper be 
united in equal weights, the computed or ma- 
thematical specific gravity of the alloy b the 
arithmetical mean of the two specific gravi- 
ties. This error was pointed out by me in a 
paper publistied in the 7th number of the 
Journal of Science and the Arts; and the 
correct rule was at the same time given. The 
details belong to the article Specific Gravity ; 
but the rule merits a place here. The spe- 
cific gravity of the alloy is found by dividing 
the sum of the weights by the sum of the 
volumes, compared to water, reckoned unity. 
Or, in another form, the rule may be stated 
thus :•— Multiply the sum of the weights into 
the product of the two specific gravities for 
a numerator, and multiply each specific gra- 
vity into the weight of the other body, and 
add the two products together for a denomi- 
nator. The quotient detained by dividing 
the numerator by the denominator, is the true 
compuied mean specific gravity; and that 
found by experiment, being compared with it, 
will show whether expansion or condensation 
of volume has attended the chemical combi- 
nation. Gold having a specific gravity of 
19.36, and copper of 8.87, being alloyed in 
equal weights, give on the ftdladous rule 
of the arithmetical mean of the densities, 

— I—X-J — = 14i.ll ; whereas the rightly 

calculated mean specific gravity is only 12. 16. 
It is evident, that by comparing the former 
number with chemical experiment, we should 
be led to infer a prodigious condensation of 
volume beyond what really occurs. 

A circumstance was observed by Mr Hat- 
chett to influence the density of metals, which 
a priori might be thought unimportant 
When a bar of gold was cast in a vertical 
position, the density of the metal at the lower 
end of the bar was greater than that of the 
top, in the proportion of 17.364 to 17.035. 
Are we to infer that melted metal is a com- 
presnble fluid, or rather, that particles pass- 
ing into the solid state under pressure, exert 
their cohesive attraction with adventitious 
strength? Under the title MeUd, a tabular 
view of metallic combinations will be found, 
and under that of the particular metal, the 
requisite information about its alloys. 



ALLUVIAL FORMATION8»in9BoJ 
logy* arc recent deposits in valleys or in pUdna, 
of the detriiut of the neighbouring mountains. 
Gravel, loam, clay, sand, brown coal, wood 
coal, bog iron ore, and calc tufil^ compose the 
alluvial depoaita. Tlie gravel and «md some- 
times contain gold and tin, if the ores exist 
in the adjoining mountains. Petrified wood 
and animal skeletons are found in the allu- 
vial clays and sand. 

ALMA N DINE. Precious garnet 
ALMONDS. Sweet aimondt are com-* 
posed, by M. Boullay, of 

Water, ... - aSO 
FelUcle, .... 5.00 
fine oil, ... 54.00 
Albumen, ... 24.00 
Liquid sugar, ... 6.00 
Gum, .... aOO 
Fibrous matter, - <- 4.00 

Loss and acetic add, - 0.50 



100.00 
Biiler aimondt consist, according to M. 
Vogel, of 

Envelope, ... 8.5 

Fat oil, .... 2aO 
Caseous matter, - - 30.0 • 

Sugar, .... 6.5 

Gum, - - - - aO 

Vegetable fibre, - . , . &0 
Dense volatile oil, 
Fhissic add, ... 

100.0 
The volatile oil, at first liquid, becomes 
solid, and crystallizes by contact vnth air: it 
communicates to water the taste and smell 
of hydrocyanic add, without giving it the 
property o^ forming prussian blue with iron. 
Dogs on swallowing some of it instantly died. 
It is colourless, has an acrid burning taste, 
denser than water, very soluble in ether and 
alcohol, very inflammable^ and consists in- 
deed of two quite distinct spedes €f oil, 
which may be easily separated in distillation 
by apportioning the products. Tlie least 
volatile is not poisonous, and experience no 
alteration in azote, hydrogen, carbonic add ; 
but with air or oxygen it speedily takes into 
a crystalline mass by oxidation. In this new 
state it reddens litmus, and continues to do 
so whatever purification it may receive. It 
is fusible, volatile^ soluble in boiling water ; 
from which it falls down in crystals by cool- 
ing. It combines with alkalis, and may per- 
haps, from its several properties, be regarded 
as an acid. 

Tlie more volatile oil does not solidify on 
contact with air ; it is so poisonous, that a ' 
very small dose of it kills animals in a few 
seconds. Alkalis have no action on it at 
ordinary temperature ; but when heated to- 
gether, an alkaline hydrocyanate b produced, 
a crystaUixable matter different from the- 



AI/T 



199 



ALU 



thosfe, and ftbo an aod, md a raaiiioui 
matter* 

ALOE& This is a bitter juice^ extracted 
from the leaves of a plant of the same name. 
Three sorts of aloes are distinguished in the 
shops by the names of aloe soccotrina, aloe 
bepatica, and aloe caballina. It is certain, 
however, that the different kinds are all pre- 
pared at Monriedro in Spain, from the same 
leaves of the common aloe. Deep incisions 
are made in the leaves, from which the juice 
is suffered to flow ; and this, after decanta- 
tion from its sediment, and inspissation in 
the sun, b exposed to sale in leathern bags 
by the name of soccotrine aloes. An addi- 
tional quantity of juice is obtained by pres- 
sure from the leaves ; and this, when decant- 
ed from its sediment and dried, is the hepatic 
aloes. And lastly, a portion of juice is ob- 
tained by strong pressure of the leaves, and 
k mixed with the dregs of the two preceding 
kinds to form the caballine aloes. The first 
kind is said to contain much less resin. The 
principal characters of good aloes are these: «— 
it nnist be glossy, not very black, but brown ; 
when rubbed or cut, of a yellow colour; 
compact, but easy to break ; easily soluble ; 
of an unpleasant peculiar smell, which can- 
not be described, and an extremely bitter 



Aloes appears to be an intimate combi- 
nation of gummy resinous matter, so well 
blended together, that watery or spirituous 
solvents, separately applied, dissolve the 
greater part of both. It is not determined 
whether there be any difference in the medical 
properties of these solutions. Both are pur- 
gative, as is likewise the aloes in substance ; 
and, if used too freely, are apt to prove heat- 
ing, and produce hemorrhoidal complaints. 

Braoconot imagines he has detected in 
aloes a peculiar principle, similar to the bit" 
ter resinous which Vauqoelin has found in 
many febrifuge barks. The recent juice of 
the leaves absorbs oxygen, and becomes a fine 
reddishp-purple pigment . 

According to M, Liebeg, the bitter of aloes 
is plentifully obtained by the action of nitric 
add of sp. gr. 1.25. This is the aloetic 
add of M. Braconnot With potash it forms 
a purple salt, which is but slightly soluble, 
which predpitates the salts of baryta, lead, 
and peroxide of iron, in flocks of a deep 
purple colour ; the protonitrate of mercury 
is predpitated of a light red. 

This substance, when purified, is the same 
with carbazotic acid, which see. The bitter 
of aloes is a compound of a peculiar sub- 
stance, possessing the properties of the resins, 
and carbaxodc add. 

Wool, morphia, narcotin^ and myrrh, 
yielded no carbasotic add, when treated with 
nitric add. 

ALTHEINE. The name of a supposed 
new vegetable prindple, extracted from the 



roots of atihea offlcinaHs; but it has been 
shown to be identical with asparagiiu 

ALUDEL. The process of sublimation 
di£fers from distillation in the nature of ita 
product, which, instead of becoming con- 
densed in a fluid, assumes the solid state, 
and Ihe form of the recdvers may of course 
be very different The recdvers for subli- 
mates are of the nature of chimnies, in which 
the elastic products are condensed, and adhere 
to their internal surface. It is evident that 
the head of an alembic will serve very wdl 
to recdve and condense such sublimates as 
are not very volatile. The earlier chemists 
thought proper to use a number of similar 
heads, one above the other, communicating 
in succession by means of a perforation in 
the superior part of each, which recdved the 
neck of the capital immediately above it 
These head% differing in no respect from the 
usual heads of alembics, excepting in tbdr 
having no nose or beak, and in the other dr- 
cumstances here mentioned, were called alu- 
dels. They are seldom now to be seen in 
chemical laboratories, because the operations 
of this art may be performed with greater 
simplidty of instruments, provided attention 
be pud to the heat and other circumstances. 
ALUM. See Alumina (Sulphate of.)- 
ALUM-EARTH. A massive mineral, 
of a blackish-brown colour, a dull lustre, an 
earthy and somewhat slaty fracture, sectile, 
and rather soft. By Klaproth*s analysis it 
contains, charcoal 19.65, silica 40, alumina 
16, oxide of iron 6.4s sulphur 2.84s sulphates 
of lime and potash each 1.5, sulphate of iron 
1.8, magnesia and muriate of potash 0.5, and 
water 10.75. 

ALUM-SLATE. 1. Common. This 
mineral occurs both massive and in insulated 
balls of a greyish-black colour, dull lustre, 
straight slaty fracture, tubular fragments, 
streak coloured like itself. Though soft, it- 
is not very brittle. Eflloresces, acquiring the 
taste of alum. 

2. Glossy Alum-slate. A massive mineral 
of a bluish-black colour. The rents display 
a variety of lively purple tints. It has a 
semi-metallic lustre in the fracture, which is 
strsight, slaty, or undulating. There is a 
soft variety of it, approaching in appearance 
to slate clay. By exposure to air its thick- 
ness is prodigiously augmented by the for- 
mation of a Miline efflorescence, which sepa- 
rates its thinnest plates. These afterwards 
exfoliate in brittle sections, causing entire 
disint^ration. 

ALUMINA. One of the primitive earths, 
which, as constituting the plastic prindple of 
all clays, loams, and boles, was called argil 
or the argillaceous earth, but now, as bdng 
obtdned in greatest purity from alum, is 
styled alumina. It was deemed elementary 
matter till Sir H. Davy's celebrated electro- 
chemical researches led to the belief of its 



ALU 140 ALU 

being, like baryta and lime, a mptalKc ox- the same illustrious chemist, a strong red hdat 
ide. only being applied to the alumina, a mass 

Tlie purest native alumina is found in the was obtained, which took, fire spontaneously 
oriental gems, the sapphire and ruby. They by exposure to the air, and which eflerresced 
consist o£ nothing but this earth, and a small violently in water. This mass was probably 
portion of colouring matter. The native an alloy of aluminum and potassium. Hie 
porcelain clays or kaolins, however white and conversion of potassium into its oxide^ dry 
soft, can never be regarded as pure alumina, potash, by alumina, proves the presence of 
They usually contain fully half their weight oxygen in the latter. 

of silica, and frequently other earths. To M. Woehler has discovered a method of 
obtain pure alumina, we dissolve alum in 20 preparing aluminum, founded on the inoxt* 
times its weight of water, and add to it a lit- dability of this metal by water ; and he 
tie of the solution of oubooate of soda, to makes chloride of aluminum, for the pur- 
throw down any iron which may be present pose of procuring the metal from it, by 
We then drop the supernatant liquid into a the following process. Alumina precipitated 
quantity of the water of ammonia, taking care by excess of cart)onate of potash, was well 
not to add so much of the aluminous solution washed and dried, and then made into a 
as will saturate the ammonia. The volatile thick paste with powdered charcoal, sugar, 
alkali unites with the sulphuric acid of the and oil : this paste was then heated in a 
alum, and the earthy basis of the latter is sepa- covered crucible till all the organic mal|^ 
rated in a white spongy precipitate, lliis was destroyed. By these means, any sub- 
must be thrown on a filter, washed, or eduU stance is mixed very intimately with carbon, 
corated, as the old chemists expressed it, by The product, while it was hot, was put into 
repeated affusions of water, and then dried, and made to fill a porcelain tube, which was 
Or if an alum, made with ammonia instead placed in a furnace of an oblong form. One 
of potash, as is the case with some French end of the tube was connected with another 
alums, can be got, simple ignition dissipates tube, containing fused chloride of calcium,' 
its acid and alkaline constituents, leaving pure and this with an apparatus for the disengage- 
alumina. ment of chlorine : tlie other end of the tube 

Alumina prepared by the first process is opened into a small tubulated receiver, pro- 
white, pulverulent, soft to the touch, adheres vided with a conducting tube. When the 
to the tongue, forms a smooth paste without apparatus was full of chlorine^ the tube and 
grittiness in the mouth, insipid, inodorous, its contents were made red-hot. The chlo- 
produces no change in vegetable colours, in- ride of aluminum was readily formed ; a 
soluble in water, but mixes with it readily in small portion was carried over with oxide of 
every proportion, and retains a small quantity carbon, which fumed strongly on coming 
with considerable force ; is infusible in the into contact with the air. l^e chlorine was 
strongest heat of a furnace, experiencing long retained by the mass of matter. The 
merely a condensation of volume and cons^ receiver contained chloride of aluminum in 
quent hardness, but is in small quantities the state of powder. After an hour and a 
melted by the oxyhydrogen blowpipe. Its half, the diloride obstructed the end of the 
specific gravity is 2.000, in the state of pow- tube (although an inch in diameter) which 
der, but by ignition it is augmented. passed into the receiver ; this caused the 

Every analogy leads to the belief that alu- stoppage of the process, 
mina contains a peculiar metal, which may be On taking the apparatus to pieces it was 

called aluminum. The first evidences ob- found, that all that part of the tube which 

tained of this position are presented in Sir H. passed through the furnace was filled with 

Davy's researches. Iron negatively electri- chloride of aluminum, and it weighed more 

fied by a very high power, being fused in con- than an ounce. It consisted partly of an 

tact with pure alumina, formed a globule aggregation of long crystals, and partly of a 

whiter than pure iron, which effervesced firm mass, of a pale yellowish-green colour, 

slowly in water, becoming covered with a semitranspareut, and of a lamellated and dis- 

white powder. The solution of this in muri- tinctly crystalline texture. When brought 

atic acid, decomposed by an alkali, afforded into contact with the air, it fumed feebly, 

alumina and oxide of iron. By passing pot- gave a smell of muriatic acid, and soon be- - 

assium in vapour through alumina heated to came a transparent fluid. When thrown 

whiteness, the greatest part of the potassium into water, it dissolved with strong hissing, ' 

became converted into potash, which formed accompanied with so much heat, tliat the 

a coherent mass with that part of the alumina fluid, when its quantity is small, boils rapid- 

not decompounded ; and in this mass there ly. Its fusing and vaporizing points appear • 

were numerous grey particles, having the me- to be the same. 

tallic lustre, and which became white when Chloride of aluminum may be preserved 

heated in the air, and which slowly effervesced without any alteration in naphtha : when 

in water. In a similar experiment made by healed with this oil, it liquefies, and dnks to 



ALU 141 ALU 

the bottom of the vetsel in the fonn of a at iu boiling point, tlie metal is slowly oxi- 

reddiab-brown liquid, upon which potassium dized, and hydrogen is liberated. 

exerts no action. Sulphuric and nitric acids, when cold, do 

When an attempt is made to heat chloride not act upon aluminum : when heated, con-* 

of aluminum with potassium in a tube^ the centrated sulphuric acid readily dissohes it, 

action is so strongs and the extrication of heat and without the disengagement of sulphu- 

is so considerable, that the apparatus is in- rous acid. The sulphuric solution did not by 

slantly broken. M. Woehler, Uierefore, em- evaporation give the smallest crystal of alum. 
ployed a small platina crucible, the cover of Aluminum dissolves in even a weak solu- 

which was kept on by a wire of the same tion of caustic potash, with the evolution of 

metal. At the moment of reduction, the hydrogen, and the same solution takes place 

crucible became intensely red-hot, both with- in ammonia. 

in and without, although it was but slightly When aluminum is heated to dull redness 
heated : the metal of the crucible was not and exposed to a current of chlorine, it in- 
sensibly acted on. Some small pieces of flames, and is converted into chloride^ which 
potassium of about the size of a pea, and not sublimes as fast as it is formed. 
more than ten at once^ are placed in the cru- Sutphuret of aluminum is formed by let- 
dble;, and upon them are put an equal num* ting sulphur drop upon aluminum in a state 
ber of pieces of chloride of aluminum of the of vivid ignition. It is semi-metallic in ap- 
same sise. The crucible is to' be heated with pearance, and, when polished, is of a shining 
the spirit-lamp, at first gently, and afterwards iron-black colour. M. Woehler formed also 
more strongly, and until the spontaneous in- the pbosphuret, seleniuret, arseniuret, and 
candescence of the matter ceases. Excess teWuretot aiuminum, -^Hentman*t Repertoire 
of potassium is to be avoided ; for, after it de Chimie, Jan, 1828. 
was oxidised, it would dissolve a portion of When regarded as an oxide, Sir H. Davy 
the aluminum. The reduced mass is gene- estimates its oxygen and basis to be to one 
rally completely fused, and is of a blackish- another as 15 to 33, or as 10 to 22. The 
grey colour. Wlien all is cold, the crucible prime equivalent of alumina would thus ap- 
is to be thrown into a large vessel of water : a pear to be 1.0 -f- 2.2 ^ 3.2. 
grey powder is soon deposited, which, when But Berzelius*s analysis of sulphate of alu- 
looked at in the sunshine, appears to be mina seems to indicate 2. 136 as the quantity 
entirely composed of small metallic plates, of the earth which combines with 5 of the 
The powder is to be washed with cold water, acid. Hence aluminum will come to be re- 
tad then dried. It is the metal of alumina, presented by 2.136 — 1, s: 1.136. Wo 

Aluminum somewhat resembles platinum shall presently show that his analysis, both 

in powder. Some small scaly coherent par* of alum and sulphate of alumina, may be 

tides were discerned, which had the colour reconciled nearly to Sir H. Davy's equivalent 

and splendour of tin. Under the burnisher prime =: 3.2. That of aluminum will be* 

it readily assumes the appearance of this come of course 2.2. 

metal. Rubbed in an agate mortar, it seems Alumina which has lost its plastirity by 

to be a little compressible^ and unites into ignition, recovers it by being dissolved in an 

kuger scales, .with a metallic lustre ; and it acid or alkaline menstruum, and then preci- 

leaves in the mortar traces of a metallic ap- pitated. In this state it is called a hydrate, 

pearance. When heated in the air till it is for when dried in a steam-heat it retains 

ignited, it inflames, and bums with great much water ; and therefore resembles in oom- 

rapidity. The product is the white oxide position wavdlite,-^ beautiful mineral, con- 

of aluminum in a hard mass. Reduced to sisting almost entirely of alumina, with about 

powder, and blown upon in the flame of a 28 per cent of water. Alumina is widely 

candle, each particle suddenly becomes an diffused in nature. It is a constituent of 

inflamed point, the splendour of which is every soil, and of almost every rock. It is 

not less than that of the spcurks of iron the basis of porcelain, pottery, bricks, and 

burning in oxygen gas. In pure oxygen crudbles. Its affinity for vegetable colouring 

gas, duminum bums with so dazzling a matter is made use of in the preparation of 

li^t, that the eyes can scarcdy bear it ; the lakes, and in the arts of dyeing and cdico- 

beat generated is so considerable, that the printing. Native combinations of dumina 

oxide produced is partly fused. The par- constitute the fuller's earth, ochres, bolea^ 

ijcles which have been fused are yellowish, pipe clays, &c 

and as harvi as corundum; they do not ALUMINA (SALTS OF). These salta 

merdy scratch, but they cut glass. In order have the following generd charactera :— 
that duminum may bum in oxygen gas, it I. Most of them are very soluble in 

must be heated to redness. water, and thdr solutions have a sweetish 

Aluminum is not oxidized by water, and acerb taste, 
this fluid may spontaneously evaporate from 2. Ammonia throws down their earthy 

the metal, without its being in the least tar- base, even though they have been preriously 

ilishcd. When, however, the water is nearly addulated with muriatic add. 



ALU 142 ALU 

3. At a strong red heat tbey give out a lignoiu, would require about 2^ Un. of alum 

portion of their acid. for eiact decomposition. Tlie excess em- 

, 4. Phosphate of ammonia gives a white ployed is found to be useful, 
precipitate. The affinity between the constituents of 

5. Hydriodate of potash produces a floe- tiiis salt is very feeble. Hence the attractionr 
culent precipitate of a white colour, passing of cotton fibre for alumina, aided by a mo* 
into a permanent yellow. derate heat, is sufficient to decompose it 

6. They are not affected by oxalate of am- The following salts of alumina are insolu- 
monia, tartaric acid, ferroprussiate of potash, ble in water :— Arseniate^ borate, phosphate, 
or tincture of galls. By the first two tests tungstate, mellatc^ saclactate, Utfaate, nsalate, 
they are distingmshable from yttria, and by camphorate. The oxalate is uncrystallizable. 
the last two from that earth and gludna., It consists of 56 acid and water, and 44 alu- 

7. If bisulphate of potash be added to a mina. The tartrate does not crystallize, 
solution of an aluminous salt, moderately con- Bnfc the tartrate of potash and alumina is 
centrated, octahedral crystals of alum will remarkable, according to Thenard, for jrield- 
form. ing no precipitate^ cither by alkalis or alkaline 
. AceiaU of Alumina, By digesting ttrong carbonates. The supeigallate crysfalliaes. 
acetic acid on newly precipitated alumina, this There seems to be no dry carbonate. A 
saline combination can be directly formed, supernitrate exists very difficult to crystsUiie. 
Vin^ar of ordinary strength scarcely acts on Its specific gravity is 1.645. A moderate 
the earth. But the salt is seldom made in heat drives off the acid. Tlie muriate is 
this way. It is prepared in large quantities easily made by digesting muriatic add on 
for the calico printers, by decomposing alum gelatinous alumina. It is colourless, astrin- 
with acetate of lead ; or more economically gent, deliquescent, uncrystallizable, reddena 
with aqueous acetate of lime, having a specific turnsole, and forms a gelatinous mass by 
gravity of about 1.050 ; a gallon of which, evaporation. Alcohol dissolves at 60^ half 
equivalent to nearly half a pound avdrdu- its weight of this salt. A dull red heat se- 
pois of dry aoetic add, is employed for every parates th^ acid from the alumina. Its com- 
2| lb. of alum. A sulphate of lime is formed position is, according to Bucholz, 29.8 acid, 
by complex affinity, which precipitates, and 30.0 base, 40.2 water, in 100 parts. 

an acetate of alumina floats above. The Sulphate of tUumina exists under several 

above proportion of alum is much beyond the modifications. The simple sulphate is easily 

equivalent quantity ; and the spedfic gravity made, by digesting sulphuric add on pure 

of the liquid is consequently raised by the clay. The salt thus formed crystallizes in 

ezcess of salt It is usually 1.080. By thin soft plates, having a pearly lustre. It 

careful evaporation capillary crystals are has an astringent taste^ and is so soluble in 

formed, which readily deliquesce. M. Gay water as to crystallize with difficulty. When 

Lussac made some curious observations on moderately heated tlie water escapes, and, at 

the solutions of this salt. Even when made a higher temperature, the acid. Berzelius 

with cold saturated solutions of alum and has chosen this salt for the purpose of deter- 

acetate of lead, and consequently but little mining the equivalent of alumina. He con- 

concentrated, it becomes turbid when heated siders the dry sulpliate as a compound of 100 

to 1229 Fahr. ; and at a boiling heat a pred- parts of sulphuric add with 42.722 earth, 

pitate falls of about one-half of the whole salt. This makes the equivalent 21.361, oxygen 

On cooling it redissolved. This decomposi- being reckoned 10, if we consider it a com* 

tion by heat, which would be prejudicial to pound of a prime proportion of each. But 

Ifae calico printer, is prevented by the excess if we regard it as consisting of 3 of acid 

of alum which b properly used in actual and 2 of base, we shall have 32.0 for the 

practice. M. Gay Lussac thinks this phe- prime equivalent of alumina. Tlie reason for 

nomenon has considerable analogy with the asrigning this number will appear in treating 

coagulation of albumen by heat ; the particles of the next salt 

of the water and of the solid matter, being ALUM. This important salt has been 
carried by the heat out of their sphere of ac- the object of innumerable researches both with 
tivity, separate. It b probably a subacetate regard to its fabrication and composition, 
which falls down, as wdl as that which b ob- It is produced, but in a very small quantity, 
tfuned by drying the crystals. Wenzel's in the native state, and thb b mixed with he- 
analysis of acetate of alumina gives 73.81 terogeneous matters. It effloresces in various 
add to 26.19 base, in 100 parts. If we sup- forms upon ores during caldnation, but it 
pose it to consist, like the sulphate, of three seldom occurs crystallized. The greater part 
primes of acid to two of alumina, we shall of this salt is factitious, being extracted from 
have for its equivalent proportions, 20 of dry various minerals called alum ores ; such as, 
add -f- 6.4 earth, or 75.8 -f- 24.2 ss 100. 1. Sulphuretted clay. This constitutes the 
As alum contains, in round numbers, about purest of all aluminous ores, namely, that of 
lw9th of earthy base, 8 oz. of real acetic acid la Tolfa, near Civita Vecchia in Italy. It is 
present in the gallon of the redistilled pyro- white, compact, and as hard as indurated day, 



ALU 



J48 



ALU 



viicnce it is caHed petra tdmmatam- It is 
tasteless and mealy. One hundred parts of 
tills ore contain above forty of sulphur and 
fiflj of ciayy a small quantity of potash, and 
« little iron. Bergman says it contains 
^9ffty-tfaree of sulphur in one hundred, thirty- 
five of clay, and twenty-two of siliceous 
earth. Iliis ore is first torrefied to acidify 
the sulphur, which then acts on the clay, and 
forms the alum. 

2. The pyritaceousclay, which is found at 
Schwcmsal, in Saxony, at the depth of ten or 
twelve feet. It is a black and hard, but 
brittle substance, consisting of clay, pyrites, 
and bitumen. It is exposed to the air for 
two years; by which means the pyrites is 
decomposed, and the alum is formed. The 
alum ores of Hesse and Liege are of this 
kind ; but they are first torrefied, which is 
said to be a disadvantageous method. 

3. The schistus aluminaris contains a va- 
riable proportion of petroleum and pyrites 
intimately mixed with it When the Last are 
in a very large quantity, this ore is rejected 
as containing too much iron. Professor Berg- 
man very properly suggested, that by adding 
a proportion of clay, this ore may turn out 
advantageously for producing alum. But 
if the petrol be considerable, it must be tor- 
refied. The mines of Becket in Normandy, 
and those of Whitby in Yorkshire^ are of this 
species. 

4w Volcanic aluminous ore. Such is that 
oi Solfaterra near Naples. It is in the form 
of a white saline earth, after it has effloresced 
in the air ; or else it is in a stony form. 
' 5. Bituminous alum ore is called shale, 
and is in the form of a schistus, impr^nated 
with so much oily matter, or bitumen, as to 
be infiammable. It is found in Sweden, and 
also in the coal mines at Whitehaven, and 
cisewhere. 

Cbaptal fiibricated alum on a large scale 
from its component parts. Hie purest and 
whitest day being made into a paste with 
water, and formed into balls half a foot in 
diameter, these are c^cined in a furnace, 
broken to pieces, and a stratum of the frag- 
ments laid on the floor. A due proportion 
of sulphur is tbeix ignited in a chamber, in 
the same manner as for the fabrication of sul- 
phuric add; and the fragments of burnt 
day, imbibing thb as it forms, begin after a 
f<^ days to crack and open, and exhibit an 
e^oresoence of sulphate of alumina. When 
the earth has completely effloresced, it is taken 
out of the chamber, exposed for some time 
in an open shed, that it may be the more in- 
timately penetrated by the arid, and is then 
lixiviated and crysuUized in the usual man- 



Hie most extensive alum manufactory in 
Great Britain is at Hurlett, near Paisley, on 
the estate of the Earl of Gla^ow. The next 
in magnitude is at Whitby: of whose state 



and prooeaaes an instructive account was pub- 
lished by Mr Winter in the 85th volume of 
Nicholson's Journal. The st i atuui of alu- 
minous schistus is about 29 miles in widtl^ 
and it is covered by strata of alluvial soil, 
sandstone, ironstone, shell, and clay. The 
alum schist is generally found disposed in 
horixontal laminie. The upper part of the 
rock is the most abundant in sulphur; so 
that a cubic yard taken from the top of the 
stratum is five times more valuable than the 
same bulk 100 feet below. 

If a quantity of the schistus be laid in a 
heap, and moistened with sea-water, it will 
take fire spontaneously, and will continue to 
bum till the whole inflammable matter be 
consumed. Its colour is bluish-grey. Its 
sp. grav. is 2.48. It imparts a bituminous 
prindple to alcohol. Fused with an alkaU, 
muriatic add predpitates a large proportion 
of silex. 

The expense of digging and remoring to a 
distance of 200 yards one cubic yard of the 
schistose rock, is about sixpence-halfpenny. 
A man can earn from 2t. 6d. to 3s. a^^ay. 
The rock, broken into small pieces, is laid on 
a horixcmtal bed of fuel, composed of brnsh- 
vrood, &c When about 4 feet in height of 
the rock is piled on, fire is set to the bottom, 
and fresh rock continually poured upon the 
pile. This is continued until the caldned 
heap be raised to the bright of 90 or 100 feet. 
Its horisontal area has also been progressivdy 
extended at the same time, till it forms a 
great bed nearly 200 feet square, baring about 
10(^000 yards of solid measurement The 
rapidity of the combustion is allayed by plas- 
tering up the crevices with small schist moist- 
ened. Notwithstanding of this precaution, a 
great deal of sulphuric or sulphurous add is 
dissipated. 1 30 tons of caldned schist pro- 
duce on an average one ton of alum. This 
result has been deduced from an average of 
150,000 tons. 

The caldned mineral is digested in water 
contained in pits that usually contain about 
60 cubic yards. The h'quid is drawn off into 
dstems, and afterwards pumped up again 
upon fiesh caldned mine. This is repeated 
until the specific grarity becomes 1.15. Hie 
half-exhausted schist is then covered with wa- 
ter to take up the whole soluble matter. The 
strong liquor is drawn ofi* into settling ds- 
tems, where the sulphate of lime^ iron, and 
earth, are deposited. At some works the li- 
quid is boiled, which dds its purification. It 
is then run into leaden pans ten feet long, 
four feet nine inches wide, two feet two inches 
deep at the one end, and two feet dght inches 
at tlie other, litis slope makes them be easily 
emptied. Here the liquor is concentrated at 
a boiling heat Every morning the pans are 
emptied into a settling dstem, and a solution 
of muriate of potash, dther pretty pure from 
the manufacturer, or crude and compound 



ALUM. 



lU 



ALUM. 



ironi tbe soap-boiler, u added. Hie quantity 
of muriate necessary is determined by a pre- 
▼ious experiment in a basin, and is regulated 
for the workmen by the hydrometer. By this 
addition, the pan liquCM', which had acquired 
a specific gravity of 1.4 or 1.5, is reduced to 
1.35. AtW being allowed to settle for two 
hours, it is run off into the coolers to be crys- 
tallixed. At a greater sp. gravity than 1.35, 
the Uquor, instead of crystallizing, would, 
when it cools, present us with a solid magma, 
resembling grease. Urine is occasionally 
added, to bring it dowii to the proper den- 
sity. 

After standing four days the mother waters 
are drained off, to be pumped into tbe pans 
on the succeeding day. The crystals of alum 
are washed in a tub, and drained. They are 
then put into a lead pan, with as much water 
as will make a saturated solution at the boil- 
ing point Whenever this is effected, the so- 
lution is run off into casks. At the end of ten 
or sixteen days, tbe casks are unhooped and 
taken asunder. TTie alum is found exteriorly 
in a solid cake, but in the interior cavity in 
large pyramidal cr3rstal8, consisting of octa- 
edrons, inserted successively into one an- 
other. This last process is called roching. 
Mr Winter says, that 22 tons of muriate of 
potash will produce 100 tons of alum, to 
which 31 tons of the black ashes of the soap- 
boiler, or 73 of kelp, are equivalent. Where 
much iron exists in the alum ore, the alkaline 
muriate^ by its decomposition, gives birth to 
an uncrystallizable muriate of iron. The 
alum manufactured in the preceding mode is 
a sulphate of alumina and potash. Hiere is 
another alum which exactly resembles it 
This is a sulphate of alumina and ammonia. 
Both crystallize in regular octaedrons, formed 
by two four-sided pyramids joined base to 
base. Alum has an astringent sweetish taste. 
Its sp. gravity is about 1.71. It reddens 
the vegetable blues. It is soluble in 16 parts 
of water at 60^, and in |ths of its weight at 
212^. It effloresces superficially on exposure 
to air, but the interior remains long unchang- 
ed. Ita water of crystallization is sufiicient 
at a gentle heat to fuse it If the heat be in- 
creased it froths up, and loses fully 45 per 
cent of its weight in water. The spongy re- 
sidue is called burnt or calcined alum, and is 
used by surgeons as a mild escharodc. A 
violent heat separates a great portion of its 
add. 

Roman alum is crystallized in cubes, be- 
cause the solution from which the final cry». 
tals are obtained, is never suffered to attain 
a higher temperature than 104P F. When 
this cubical alum is dissolved, and its solu- 
tion heated to temperatures above 110^ F. 
a precipitate of sulphate of alumina is pro- 
duced, and the solution vrill now yidd only 
octahedral crystals. Hence may be deduced 



the means of obtaining either cubical or octa- 
hedral alum at pleasure. 
Alum was thus analyzed by Berzelius :— Ist, 
20 parts (grammes) of pure alum lost by the 
heat of a spirit lamp 9 parts, which gives 4S 
per cent of water. The dry salt was dissolv- 
ed in water, and its acid precipitated by tbe 
muriate of baryta; the sulphate of whicfay 
obtained after ignition, weighed 20 parts ; in- 
dicating in 100 parts 34i.3 of dry sulphuric 
acid. 2d, Ten parts of alum were dissolved 
in water, and digested with an excess of am- 
monia. Alumina, well washed and burnt, 
equivalent to 10.67 per cent, was obtained. 
In another experiment 10.86 per cent result- 
ed. 3d, Ten parts of alum dissolved in water 
were digested with carbonate of strontia, 
till the c«rth was completely separated. The 
sulphate of potash, after ignition, weighed 
1.815, corresponding to 0.981 potash, or, in 
100 parts, to 9.81. 

Alum, therefore, consists of 

Sulphuric acid» 34.33 

Alumina» ia86 

Potash, 9.81 

Water, 45.00 



100.00 
or, Sulphate of alumina, 36.85 
Sulphate of potash, 1 a 1 5 
Water, 45.00 



100.00 
Thenard*s analysis, Ann. de Chimie, vol. 
59. or Nicholson's Journal, vol. 18.coinddea 
perfectly with that of Berzelius in the product 
of sulphate of baryta. From 400 parts of 
alum, he obtained 490 of the ignited barytic 
salt ; but the alumina was in greater propor- 
tion, equal to 12.54 per cent, and the sulphate 
of potash less, or 15.7 in 100 parts. 

Vauquelin, in his lastanalysiB, found 48w56 
water ; and by Thenard*s statement there are 
indicated 34.23 dry acid, 
7.14 potash, 
12.54 alumina, 
46.09 water. 



100.00 
If we rectify Vauquelin's erroneous esti- 
mate of the sulphate of baryta, his analysis 
will also coincide with the above. Alum, 
therefore, differs from the simple sulphate of 
alumina previously described, which consisted 
of 3 prime equivalento of add and 2 of earth, 
merdy by its assumption of a prime of sul- 
phate of potash. It is probable that all the 
aluminous salts have a similar constitution. 
It is to be observed, however, that the num- 
ber 34.36 resulting from the theoretic pro- 
portions, is, according to Gilbert's remarks 
on the essay of Berzelius, the just representa- 
tion of the dry add in 100 of sulphate of 
baryta, by another analysis, which makes the 

prime of baryta 9.57. 

6 



.ALUM. 



l^ 



ALUM.« 



' Should asDmoiiift be suspected in alum, it 
may be detected, and its quantity estimated^ 
by mixing quicklime with the saline solu- 
don, and exposing the mixture to heat in a 
retort, connected with a Woolfe*s apparatus. 
The water of ammonia being afterwards sa- 
turated with an acid, and evaporated to a dry 
salt, will indicate the quantity of pure am- 
monia in the alum. A variety of alum, con- 
taining both potash and ammonia, may also 
be found. This will occur where urine has 
been used, as well as muriate of potash, in its 
fabrication. If any of these sulphates of alu- 
mina and potash be acted on, in a watery 
solution, by a gelatinous alumina, a neutral 
triple ssilt is formed, which precipitates in a 
nearly insoluble statet 

When alum in powder is mixed with flour 
or sugar, and calcined, it forms the pyropho- 
rus of Homberg. 

"Mr Winter first mentioned, that another 
variety of alum can be made with toda, in- 
stead of potash. This salt, which crystallizes 
in octahedrons, has been also made with pure 
muriate of soda, and bisulphate of alumina, 
at the laboratory of Hurlett, by Mr W. Wil- 
son. It is extremely difficult to form, and 
effloresces like the sulphate of soda. 

On the subject of soda-alum, I published 
a short paper in the Journal of Science for 
July 18)^. llie form and taste of this salt 
are exactly the same as those of common 
alum ; but it is less hard, being easily crushed 
between the fingers, to which it imparts an 
appearance of moisture. Its specific gravity 
fa 1.6. 100 parts of water at 60^ F. dissolve 
1 10 of it ; fisnning a solution, whose specific 
Ipravity is 1.296. In this respect, potash-alum 
is very different ; for 100 parte of water di»- 
•olve only from eight to nine parts, forming 
a saturated solution, whose sp. gr. is no more 
than 1.0465. Ite constituents are by my ana- 
lysis,— 

Sulphuric acid, 34^00 4 primes, 33.96 
Alumina, 10.75 3 — 10.82 

Soda, 6.48 1 — 6.79 

Water, 49.00 25 — 4a43 



100.23 100.00 

Or it consists of three primes sulphate of alu- 
mina .^ one sulphate of soda< To each of 
the former, five primes of water may be as- 
signed, and to the latter ten, as in Glauber's 
salt 

The only injurious contamination of alum 
is sulphate of iron. It is detected by ferro- 
prussiate of potash. To get rid of it cheap- 
ly, M. Thenard recommended dissolving the 
alum in boiling water, and agitating the so- 
lution with rods as it cools. The salt is thus 
reduced to a fine granular powder, M'hich 
being washed two or three tiroes with cold 
water, and drained, yields a perfectly pure 
alum. For a very advantageous mode of 
concentrating alum liquors, as well as those 



of other salts, on the great scale, see Evav 

PORATION. 

Mr Philips describes, in the 4ih volume of 
the Annals of Philosophy, N. S. a new sul- 
phate of alumina, which he obtained by put- 
ting moist alumina into dilute sulphuric acidi 
and adding more occasionally, until it re- 
mained in excess. Being now filtered, a clear 
dense solution was obtained, which, when 
dropped into water, instantly let fall a preci- 
pitate, almost as abundant as that from mu- 
riate of antimony. It also began to precipi* 
tate immediately, even of itself, though no 
tendency of this kind was observed as long 
as the excess of alumina remained mixed 
with it. The deposition went on for several 
months ; but the clear part was always pre- 
dpitable by water. Another property of this 
sulphate of alumina is, that, if heated to 160^ 
or 170° Fahr. it becomes opaque and thick, 
but, upon cooling, in a few days it becomes 
clear again. Mr Philips considers the num- 
ber 27 as representing the atom of alumfaui 
to hydrogen = 1 ; and the above salt as con- 
sisting of two atoms sulphuric add ss 40 X 
2 = 80 -^ 3 atoms alumina = 27 X 3 a 
81 ; or, on the oxygen scale, of 2 X 5 ^ 10 
add + 3.375 X 3 =» 10.125 alumina. 

Alum is used in large quantities in many 
manufactories. When added to tallow, it ren- 
ders it harder. Printers* cushions, and the 
blocks used in the calico manufactory, are 
rubbed with burnt alum to remove any 
greasiness, which might prevent the ink or 
colour from sticking. Wood sufficiently soak-* 
ed in a solution of alum, does not easily take 
fire ; and the same is true of paper impreg- 
nated with it, which is fitter to keep gun- 
powder, as it also excludes moisture. Paper 
impregnated with alum is useful in whitening 
silver, and silvering brass without heat. Alum 
mixed in milk helps the separation of ite but- 
ter. If added in a very small quantity to 
turbid water, in a few minutes it renders it 
perfectly limpid, without any bad taste or 
quality ; while the sulphuric add imparte to 
it a very sensible addity, and docs not preci- 
pitate so soon, or so well, the opaque earthy 
mixtures that render it turbid, as I have oflen 
tried. It is used in making pyrophorus, in 
tanning, and many other manufactures, par- 
ticularly in the art of dydng, in which it is 
of the greatest and most important use, by 
cleansing and opening the pores on the sur- 
face of the substance to be dyed, rendering it 
fit for receiving the colouring particles, (by 
imparting alumina to the stuff), and in this 
way making the colour fixed. Crayons gene- 
rally consist of the earth of alum, finely pow- 
dered, and tinged for the purpose. In me- 
didne it is employed as an stringent. 

M. Hollunder states, that solution of alu- 
mina in nitric acid is readily decomposed by 
the influence of the atmosphere, even at 

K 



AMBES. 



IM 



AMBER. 



•irdinarj teoiperataret, ahbough eleTation of 
temperature increases the effect. It is most 
rapid when free acid is present The floc- 
culent substance precipitated is supposed to 
be aluminum, oxidized to a higher degree 
than the alumina obtained by the ordinary 
process ; for, at the same time, the nitric add 
undergoes decomposition, and the oxide ob- 
tained is much more insoluble than ordinary 
alumina. 

ALUMINITE. A mineral of a snow- 
white colour, dull, opaque, and having a fine 
earthy fracture. It has a glistening streak. 
It is found in kidney-sliaped pieces, which 
are soft to the touch, and adhere slightly to 
the tongue. Sp. gravity 1.67. 
It consists of sulphuric acid, 19.25 

Alumina, - - 32.50 

Water, - - 47.00 

Silica, lime, and oxide of iron, 1.25 



100.00 

The above alum ore is found chiefly in the 
alluvial strata round Halle in Saxony. 

AMADOU. It is a variety of the bolelut 
igniarivst found on old ash and other trees. 
It is boiled in water to extract its soluble 
parts, then dried and beat with a mallet to 
loosen its texture. It has now the appear- 
ance of very spongy doe-skin leather. It is 
lastly impregnated with a solution of nitre, 
and dried, when it is called spunk, or Ger- 
man tinder ; a substance much used on the 
Continent for lighting fires, either from the 
collision of flint and steel, or from the sud- 
den condensation of air in the atmospheric 
pyrophore. 

AMALGAM. This name is applied to 
the combinations of mercury with other me- 
tallic substances. See Mebcury, and Ores 
OF Mebotry. 

AMBER is a hard, brittle, tasteless sub- 
stance, sometimes perfectly transparent, but 
mostly semitransparent or opaque, and of a 
glossy surface. It is found of all colours, but 
chiefly yellow or orange, and often contains 
leaves or insects. Its specific gravity is from 
1.065 to 1. 100 ; its fracture is even, smooth, 
and glossy ; it is capable of a fine polish, and 
becomes electric by friction ; when nibbed or 
heated, it gives a peculiar agreeable smell, 
particularly when it melts, tliat is at 550° of 
Fahrenheit, but then it loses its transparen- 
cy : projected on burning coals, it burns with 
a whitish flame, and a whitish*yellow smoke, 
but gives very little soot, and leaves brownish 
ashes. It is insoluble in water and alcohol, 
though the latter, whoi highly rectified, ex- 
tracts a reddish colour from it; but it is so- 
luble in the sulphuric acid, which then ac- 
quires a reddish-purple colour, and is pred- 
pitable from it by water. No other acid dis. 
solves it, nor is it soluble in essential or ex- 
pressed oils, without some decomposition and 
long digestion ; but pure alksli dissolves it 



By distillation it affords a small quantity of 
water, with a little acetic add, an oil, and a 
peculiar add. See AoD (SuoaNic). The 
oil rises at first colourless ; but, as the heat 
increases, becomes brown, thick, and empy- 
reumatic. The oil may be rectified by suc- 
cessive distillations, or it may be obtained 
very light and limpid at once, if it be put 
into a glass alembic with water, as the elder 
Rouelle directs, and distilled at a heat not 
greater than 212^ Fahr. It requires to be 
kept in stone bottles, however, to retain this 
state ; for in glass vessels it becomes brown 
by the action of light 

Amber is met with plentifully in regular 
mines in some parts of Prussia. The upper 
surface is composed of sand, under which is 
a stratum of loam, and under this a bed of 
wood, partly entire, but chiefly mouldered or 
changed into a bituminous substance. Uiv- 
der the wood is a stratum of sulphuric or ra- 
ther aluminous mineral, in which the amber 
is found. Strong sulphurous exhalations are 
often percdved in the pits. 

Detached pieces are also found occasion- 
ally on the sea-coast in various countries. It 
has been found in gravel beds near London* 
In the Royal Cabinet at Berlin there is a 
mass of 18 lbs. weight, supposed to be the 
largest ever found. Juasieu asserts, that the 
delicate insects in amber, which prove the 
tranquillity of its formation, are not £ur»> 
pean. M. Haiiy has pointed out the follow., 
ing. distinctions between melUte and copal^ 
the bodies which most closely resemble am- 
ber. Mellite is infusible by heat A bit of 
copal heated at the end of a knife takes fire^ 
melting into drops, which flatten as they fidl ; 
whereas amber bums with spitting and froth- 
ing ; and when its liquefied particles drop, 
tliey rebound from the plane which recdves 
them. The origin of amber is at present in- 
volved in perfect obscurity, though the ra« 
pid progress of v^etable chemistry promises 
soon to throw light on it Various frauds 
are practised with this substance. Neumann 
states as the common practices of woriLmen 
the two following :— The one consists in sur- 
rounding the amber with sand in an iron pot, 
and cementing it with a gradual fire for forty 
hours, some small pieces placed near the sides 
of the vessel being occasionally taken out for 
judging of the eilect of the operation. The 
second method, which he says is that most ge- 
nerally practised, is by digesting and boiling 
tlie amber about twenty hours with rape- 
seed oil, by which it is rendered both clear 
and hard. 

Werner has divided it into two sub-spedes, 
the white and the yellow ; but there is little 
advantage in the distinction. Its ultimate 
constituents are carbon, hydrogen, and oxy- 
gen. Although my experiments on the ulti- 
mate analysis of amber were conducted care- 
fully, with re-trituration and re-ignition, n# 



AMBERGRIS. 147 AMBERGRIS. 

good atomic ooofigunitioii of it occurred to whales but luch as are dead or sick, its pro- 

me. It yielded, in 100 parts, 70.68 carboD, duction is generally supposed to be owing to 

11.62 hydrogen, and 17.77 oxygen; or of disease, though some have a little too per- 

the elements of water 20 -}- hydrogen in ez- emptorily aflSrmed it to be the cause of the 

cess 9.4, independently of the carbon.— PAi7. morbid aflectioo. As no large piece has ever 

Trans* 1822. been found without a greater or less quan- 

In the second volume of the Edinburgh tity of the beaks of tlie sepia octopodia, tha 

Philosophical Journal, Dr Brewster has given common food of tlie spermaceti whisle, inter- 

an account of some optical properties of am- spersed throughout its substance, there can 

ber, from which he considers it established be little doubt of its originating in the io- 

beyond a doubt that amber is an indurated tesdnes of the whale ; for if it were occasion- 

vegetable juice ; and that the traces of a re- ally swallowed by it only, and then caused 

gular structure indicated by its action upon disease, it must much more Irequently be 

polarized light, are not the eflect o( the or- found without these^ when it is met with 

dinary laws of crystallization by which meUite floating in the sea, or tlirown upon the shoreii 

haa been formed, but are produced by the Ambergris is found of various sizes, gene- 

aame causes which influence the mechanical rally ia small fragments, but sometimes so 

condition of gum>arabic, and other gums, large as to weigh near two hundred pounds, 

which are known to be formed by the succes- When taken from the whale it is not so hard 

ave deposition and induration of vegetable as it becomes afterward on exposure to the 

fluids. air. Its specific gravity ranges from 780 to 

M. Berzelius adopts the opinion, that am- 926. If good, it adheres like wax to the edge 
ber is of vegetable origin ; that, like ordinary of a knife with which it is scraped, retains the 
resins, it has flowed fh>m vegetables, in the imprestton of tlie teeth or nails, and emits a 
state of a balsam, and has afterwards acquir- fat odoriferous liquid on being penetrated 
cd hardness gradually. Amber, according with a hot needle. It is generally brittle ; 
to this eminent chemist, contains^ve substan- but, on rubbing it witli the nail, it becomes 
cea :— 1. An odoriferous oil, in small quan- smooth like hard soap. Its colour is either 
tity. 2. A yellow resin intimately combined white, black, ash-coloured, yellow, or black« 
with this oil, dissolving freely in alcohol, ish ; or it is variegated, namely, grey ^ith 
ether, and alkalis, very fusible, and resem« black specks, or grey with yellow specks. Its 
bling ordinary vegetable resins. 3. A resin smell is peculiar, and not easy to be counten* 
soluble with diflSculty in cold alcohol, more feited. At 144° it melts, and at 212^ is vola- 
freely in hot alcohol, from which it separates tilized in the form of a white vapour. But 
on cooling as a white powder soluble in ether on a red-hot coal it bums, and is entirely dia> 
and alkalis. Hiese two resins and the vola- sipated. Water has no action on it ; acids, 
tile oil, if removed from amber by ether, and except nitric, act feebly on it ; alkalis corn- 
then obtained by evaporation of the latter in bine with it, and form a soap ; ether and the 
water, fonn a natural viscid balsam, very volatile oils dissolve it ; so do the fixed oils» 
odorous, of a clear yellow colour, and which and also ammonia, when assisted by heat ; 
gradually becomes hard, but retains some alcohol dissolves a portion of it, and is of 
odour. There is every reason for supposing great use in analyzing it, by separating its 
this to be precisely the substance from which constituent parts. According to Bouillon la 
amber originates, but, at the same time, ra- Grange, who has given the latest analysis of 
ther poorer in essential oil than at first ; and it, .3820 parts of ambergris consist of adipo- 
that tlie insoluble substances in amber have cere 2016 parts, a resinous substance 1 167» 
been gradually formed by a spontaneous aU benzoic acid 425, and coal 212. But Bu- 
teration of this balsam, but at the same time cholz could find no benzoic acid in it. I 
have enveloped one part of it, and so pre- examined two difierent specimens with con- 
served it from entire decomposition or change, siderable attention. The one yielded ben- 
4b Succinic arid dissolved with the preceding zeic add, the other, equally genuine to all 
bodies by ether, alcohol, and alkalis. 6. A appearance, afforded none. See AniFOCEaEy 
body insoluble in alcohol, ether, and alkalis, and Intestinal Concbjetiok. 
analogous in some points to the substance An alcoholic solution of ambergris, added 
found by Dr John in lac, and called by him in minute quantity to lavender water, tooth 
'ik»jmndpU of lac. This is formed in large powder, hair powder, wash balls, &c. corn- 
quantity when a solution of lac in alkali is municates its peculiar fragrance. Its retail 
precipitated by chlorine. price being in London so high as a guinea 

Amber is also used in varnishes. See Vail- per oz. leads to many adulterations. Ibese 

XISH, and Oil of Aubeb. consist of various mixtures of benzoin, lab- 

AMBERGRIS is found in the sea, near danum, meal, &c. scented with musk. Ibe 

the coasts of various tropical countries ; and greasy appearance and smell which heated 

hMalso been taken out of the intestines of ambergris exhibits, afford good cri^ma, joined 

the pbyseter raacrocephalus, the spermaceti to its solubility in hot ether and alcohoL 

whale. As it haa not been found in any It has occasionally been cmployad in mo- 



AMETHYST. 



148 



:AMM0N1A'.* 



dicine, but its use is now confined to the 
perfumer. Dr Swediaur took thirty grains 
of it without perceiving any sensible effect. 

AMBLYGONlT£. A greenish-coloured 
mineral of different pale shades, marked on 
the surface with reddish and yellowish>brown 
spots. It occurs massive and crystallized in 
oblique four-sided prisms. Lustre vitreous ; 
deavage parallel veith the sides of an oblique 
four-sided prism of IO60 10' and TT^" 5(y; 
fiacture uneven ; fragments rhomboidal ; 
translucent; hardness, as felspar; brittle; 
sp. gr. 3.0 ; intumesces with the blowpipe, 
and fuses with a reddish-yellow phosphores- 
cence into a white enamel. It occurs in 
granite, along with green topaz and tourma- 
line, near Pinig in Saxony. It seems to be 
a species of spodumene. 

AMBREINE. By digesting ambergris 
in hot alcohol, sp. gr. 0.827, the peculiar sub- 
stance called ambreine by Pelleder and Ca- 
ventou is obtained. The alcohol, on cooling, 
deposits the ambrane in very bulky and irre- 
gular crystals, which still retain a very con- 
siderable portion of alcohol. Thus obtained, 
it has the following properties : —It is of a 
brilliant white colour, has an agreeable odour, 
of which it is deprived by repeated solutions 
and crystallizations. It is destitute of taste, 
and does not act on vegetable blues. It is 
insoluble in water, but dissolves readily in 
alcohol and ether; and in much grotter 
quantity in these liquids when hot, than 
when cold. It melts at the temperature of 
86S softening at 77°. It is partly volati- 
lized and decomposed into a white smoke 
when heated above 2129. It does not seem 
capable of combining with an alkali, or of 
b^ng saponified. When heated with nitric 
acid, it becomes green and then yellow, while 
nitrous gas is exhaled. By this absorption 
of oxygen, it is converted into an acid, which 
has been called ambreic acid. This acid is 
yellowish-white, has a peculiar smell, reddens 
vegetable blues, does not melt at 212°, and 
evolves no ammonia when decomposed at 
higher temperatures. It is soluble in alco- 
hol and ether ; but slightly so in water. Am- 
breate of potash gives yellow precipitates with 
muriate of lime, muriate of baryta, sulphate 
of copper, sulphate of iron, nitrate of silver, 
acetate of lead, corrosive sublimate, muriate 
of tin, and muriate of gold.-^Jburit. de 
Pharnu v. 49. 

AMETHYST. Tlie amethyst is a gem 
of a vblet colour, and great brilliancy, said 
to be as hard as the ruby or sapphire, from 
which it only difiers in colour. This is 
called the oriental amethyst, and is very rare. 
When it inclines to the purple or rosy colour, 
it is more esteemed than when it is nearer to 
the blue. These amethysts have the same 
figure, hardness, specific gravity, and other 
qualities, as the best sapphires or rubies, and 
O0me frten the same phnces, particularly fh)m 



Persia, Arabia, Armenia, and the West' In- 
dies. The occidental amethysts are merely 
coloured crystals or quartz. See Qca&tz and 
Sapphi &E. 

AMI ANTHOIDE. A mineral, in long 
capillary filaments, of an olive-green colour, 
flexible and elastic Lustre, brilliant silky. 
It is composed of silica 47, lime 1 1, mag- 
nesia 7, oxide of iron 20, manganese 10.— 
Vauquelifu It is found at Oisans in France. 
'-'PhHip$*$ JJineralogy, 

AMIANTHU& Mountain flax. See 

ASBESTUS. 

AMIATITE. FiORiTE, or Peabl-on- 

TER. 

AMI DINE. This is a substance pro- 
duced, according to M. de Saussure, when 
we abandon the paste of starch to itself, at 
the ordinary temperature, with or without 
the contact of air. See Starch. 

AMMONIA. Called also volatUe alkalL 
We shall first consider this substance in its 
purely scientific relations, and then detail its 
manufacture on the great scale, and its uses 
in the arts. There is a saline body, formerly 
brought from Egypt, where it was separated 
from soot by sublimation, but which is now 
made abundantly in Europe, called sal am- 
moniac. From tliis salt pure ammonia can 
be readily obtained by the following process : 
Mix unslacked quicklime with its own weight 
of sal ammoniac, each in fine powder, and 
introduce them into a glass retort. Join to 
the beak of the retort, by a collar of caout- 
chouc, (a neck of an India rubber bottle 
answers well), a glass tube about 18 inches 
long, containing pieces of ignited muriate of 
lime. This tube should lie in a horizontal 
position, and its free end, previously bent 
obliquely by the blowpipe, should dip into 
dry mercury in a pneumatic trough. A slip 
of porous paper, as an additional precaution, 
may be tied round the tube, and kept moist 
with ether. If a gentle heat from a charcoal 
chauffer or lamp be now applied to the bot- 
tom of the retort, a gaseous body will bubble 
up through the mercury. Fill a little glass 
tube^ sealed at one end, with the gas, and 
transfer it, closely stopped at the other end, 
into a basin containing water. If the water 
rise instantly and fill tlie whole tube, the gas 
is pure, and may be received for examina- 
tion. 

Ammonia is a transparent, colourless, and 
consequently invisible gas, possessed of elas- 
ticity, and the other jnechanical properties of 
the atmospherical air. Its specific gravity is 
an important datum in chemical researches, 
and has been rather differently stated. Yet, 
as no aeriform body is more easily obtained 
in a. pure state than ammonia, this diversity 
among accurate experimentalists shows the 
nicety of this statical operation. MM. Biot 
and Arago make it = 0.59669 by experi- 
ment, and by calculation from its elementary 



AMMONIA.. 



H9 



gam they jutke it = a5943a Kirwan 
says, tiiat 100 cubic inches weigh 18.16 gr. 
at 30 incbesof bar. and 61^ F., which, com- 
pared to air reckoned 30.519, gives 0.59540. 
Sir H. Davy determines its density to be ^ 
0.590, with which estimate tlie theoretic caU 
cnladons of Dr Fhmt, in the 6th volume of 
the Annals of Philosophy, agree. 

This gas has an exceedingly pungent smell, 
wfil known by the old name of spirits of 
faartshom. An animal plunged into it spee- 
dlljdies. It extinguishes combustion, but 
being itself to a certain degree combustible^ 
the flame of a taper immo^sed in it is en- . 
]ai|^ before going out. By exposing this 
gaa to a very low temperature M. Bussy suc- 
ceeded in liquefying it. See Acu) (SuLPHU- 
Boos). It has a very acrid taste. Water con- 
denses it very rapidly, llie following valu- 
able table of its aqueous combinations has 
been given by Sir H. Davy. 



Sp* Gr. 


jimmotda. 


Water. 


a8750 


32.50 


67.50 


0.8875 


29.25 


70.75 


0.9000 


26.00 


74.00 


0.9054 


25.37 


74u63 





AMMONIA... 




Sp,Gr. 


Jmmonia, 


Watgr, 


a9166 


22.07 


77.93 


0.9255 


19.54 


8Q.46 


0.9326 


17.52 


82.48 


0.9385 


15.88 


84.12 


0.9435 


14.53 


85.47 


0.9476 


13.46 


86.54 


0.9513 


12.40 


87.60 


0.9545 


11.56 


88.44 


0.9573 


10.82 


89.18 


0.9597 


10.17 


89.83 


0.9619 


9.60 


90.40 


0.9692 


9.50 


90.50 



Water is capable of dissolving easily about 
one>third of its weight of ammoniacal gas, or . 
460 times its bulk. Hence, when placed in 
contact with a tube filled with this gas, water ^ 
rushes into it with explosive velocity. Fjro- 
bably the quantity of ammonia stated in 
the above table is too high by about one per . 
cenL 

Hie following table of the quantity of am- 
monia in 100 parts, by weight, of its aqueous 
combinations at successive densities, was pub- 
lished by me in the Philosophical Magaxine 
for March 1821. 



Water 


AmrsM- 


Water 


8p.gr. 


Mean 






of 


Dlain 


in 


by expe. 


specific 


Equivalent primes. 


04»a 


joa 


100. 


rixncnt 


gravity. 






100 


26.500 


7a500 


0.9000 








95 


25.175 


74.825 


0.9045 


0.90452 




Wat, Jm. 


90 


2a850 


76.150 


0.9090 


0.90909 


24 + 76, 


6tol 


85 


22.525 


77.475 


0.9133 


0.91370 


i 




80 


21.200 


78.800 


0.9177 


0.91838 


21.25+78.75, 


7tol 


75 


19.875 


80.125 


0.9227 


0.92308 


1 




70 


ia550 


81.450 


0.9275 


0.92780 


19.1+80.9, 


8tol 


65 


17.225 


82.775 


0.9320 


0.93264 


17.35 + 82.65, 


9tol 


60 


15.900 


84.100 


0.9363 


0.93750 


15.9 + 84.1, 


10 to 1 


55 


14.575 


85.425 


0.9410 


0.94241 


14.66 + 85.34, 


lltol 


50 


ia250 


86.750 


0.9455 


0.94737 


ia60 + 86.40, 


12tol 


45 


11.925 


8a075 


0.9510 


0.95238 


ll.9 + 8ai. 


14tol * 


40 


10.600 


89.400 


0.9564 


0.95744 


11.2+88.8, 


15 to 1 


35 


9.275 


90.725 


0.9614 


0.96266 






30 


7.950 


92.050 


0.9662 


0.96774 


8.63+91.37, 


20 to I 


25 


6.625 


9a375 


0.9716 


0.97297 


7+93, 


25 to 1 


20 


5.300 


94.700 


0.9768 


0.97826 


6+94, 


30tol 


15 


3.975 


d6.025 


0.9828 


0.98360 


4.5 + 95.5, 


40tol 


10 


2.650 


97.350 


0.9887 


0.9890 


3 + 97, 


60tol 


5 


1.325 


98.675 


0.9945 


0.99447 





The remarkable expannveness which am- 
numia carries into its first condensation with 
water, continues in the subsequent dilutions 
oi its aqueous combinations. This curious 
| n op erty is not peculiar to pure ammonia, but 
belongs, as I have found, to some of its salts. 
Thua sal aotmoniac, by its union with water, 
causes an enlargement of the total volume of 
the compound^ beyond the volume of the con- 
stituents of the solution. Or the specific gra- 
Ti^ of the saturated solution is leas than the 
mean sp. gravity of the salt and water. I 



know of no salts with which this phenomenon 
occurs, except the ammoniacaL 

Near the two extremities of tlie table, the 
experimental and computed specific gravities 
agree ; the reciprocal affinity thus btdandng 
the peculiar expansiveness communicated by 
the ammonia, which becomes conspicuous in 
the intermediate proportions of water and gas. 
This fact is in unison with the general laws of 
chemical combination. 

Since 73.5 grains of distilled water exist, 
in. 100 water of ammonia, specific gravity 



AMMONIA. 



150 



AMMONIA. 



0.900, which occupy die volume of 1.111, 
ooe part of water in bulk will be conyerted 
into almost exactly one and a half of such 
water of ammonia. 1 00 grains of this water 
contain 147.2 cubic inches of gas. Hence, 
one grain of water hold scondensed in such 
aqueous ammonia 2 cubic inches of the gas, 
or one volume of distilled water is united to 
S05 volumes of the gas. 

It deserves to be remarked, that one vo- 
lume of water, when converted into aqueous 
muriatic add, spedfic gravity 1.200, or into 
aqueous ammonia, sp. gr. 0.900, eipands in 
either case into a volume and a half. 

If from 998 we deduct the spedfic gravity 
of water of ammonia, expressed in three in- 
tegers, the remainder, divided by 4i, will give 
a quotient representing the quantity of real 
alkali present. This rule is exact for all such 
liquid ammonia as is commonly used in che- 
mical researches and in medidne, viz. be* 
tween sp. grav. 936 and 980, water bdng 
1000. 

Liquid ammonia, as the aqueous compound 
is termed, may therefore, like spirits, be very 
accurately valued by its spedfic gravity. But 
it differs remarkably from alcoholic mixtures 
in this respect, that the strongest ammoniacal 
liquor, when it is diluted with water, suffers 
little condensation of volume. The spedfic 
gravity of the dilute, is not far from that of 
its components. Hence having one point 
accurately, we can compute all below it, by 
paying attention to the rule given under Spe- 
anc G&Avmr. To procure aqueous ammo- 
nia, we may use either a common still and 
refrigeratory, or a Woolfe's apparatus. The 
latter should be preferred. Into a retort we 
put a mixture of two parts of slacked lime, 
and one part of pulverized sal ammoniac, 
and having connected the beak of the retort 
with the Woolfe's apparatus, containing pure 
water, we then disengage the ammonia by 
the application of heaU When gas ceases to 
be evolved, the addition of a little hot water 
will renew its disengagement, and ensure 
complete decomposition of the salt. Since 
sal ammoniac contains nearly \ its wdght of 
ammonia, ten pounds of it should yield by 
economical treatment 30 pounds of liquid, 
whose specific gravity is 0.950, which is as 
strong as the ordinary purposes of chemistry 
and medicine require ; and it will form twice 
that quantity, or 60 pounds of the common 
water of ammonia sold by apotliecaries, which 
has rarely a smaller density than 0.978 or 
0.980. Tliere is no temptation to make it 
with the ammoniacal carbonate ; but if this 
salt be accidentally present, it is instantly 
detected by its causing a milkiness in lime 
water. 

Ammoniacal gas, perfectly dry when mix- 
ed with oxygen, explodes with the electric 
spark, and is converted into water and nitro- 
gen, as has been shown in an ingenious paper 



by Dr Henry. But the aimplctt, and per- 
haps most accurate mode of resolving ammo- 
nut into its elementary constituents, is that 
first practised by M. Berthollet, the celebra^ 
ed discoverer of its composition. This con- 
sists in making the pure gas traverse very 
slowly an ignited porcelain tube of a small 
diameter. The process, as lately repeated by 
M. Gay Lussac, yielded, from 100 cubic 
indies of ammonia, 200 cubic inches of con- 
stituent gases ; of which, by subsequent ana- 
lysis, 50 were found to be nitrogen, and 150 
hydrogen. Hence we see, that the redpro- 
cal aflinity of die ammoniacal elements had 
effected a condensation equal to one-half of 
the volume of the free gases. It appears by 
the most recent determinations, that the spe- 
dfic gravity of hydrogen is 0.0694^ compar- 
ed to air as unity, and that of nitrogen 0.9722. 
Three volumes of the former will therefore 
weigh 0.2082, and one of the latter, 0.9722 ; 
the sum of which numbers, 1.1804<, divided 
by 2, ought to coincide with the experimental 
density of ammonia. Now, it is 0.5902, 
bdng an exact correspondence. And the 
ratio of tlie two wdghts, reduced to 100 
parts, will be 82.36 nitrogen to 17.64 hydro- . 
gen. To reduce ammonia to the system of 
equivalents, or to find its saturating ratio on 
that scale where oxygen represents unity, we 
have this proportion ; 9722 : 1.75 :: 1. 1804 : 
2. 125 ; so that 2. 125 may be called its prime 
equivalent. We shall find this number de- 
duced from analysis, confirmed by the syn- 
thesis of all the ammoniacal salts. 

Dr Fjrout, in an able memoir on the rele- 
tion between the spedfic gravities of gaseous 
bodies and the weights of their atoms, pub- 
lished in the 6th voL of the Annals of Phi- 
losophy, makes the theoretical weight of the 
atom of ammonia to be only 1.9375, consi- 
dering it as a compound of 1 atom of azote^ 
and 1^ atoms of hydrogen. This statement 
appears to be a logical inference from Mr 
Dalton's hypothesis of atomical combination. 
For water, the main groundwork of his ato- 
mic structure, is represented as a compound 
of one atom of oxygen with one atom of hy- 
drogen ; and this, atomical unit of hydrogen 
consists of two volumes of the gas. Hence 
three volumes of the gas must represent an 
atom and a half. Yet an atom is, by its very 
definition, indivisible. Dr Prout, in the 
38th number of the Annals, restores the true 
proportions of 3 atoms hydrogen -^ 1 azote. 
Our doctrine of equivalent primes, resting on 
the basis of experimental induction, claims 
no knowledge of the atomical constitution of 
bodies. 

The alkaline nature of ammonia is demon- 
strated, not only by its neutralizing addity, 
and changing the vegetable reds to purple 
or green, but also by its bdng attracted to 
the negative pole of a voltaic arrangement. 
When a pretty strong electric power is ap- 



AMMONIA. 151 AMMONIA. 

ptttd to annnonia in its liquid or loUcl coin- MM. Gay Luhoc and Thenard foundi bjr 
bioaiiooi^ smple decomposition is effected ; immersion in water, that mercuTy* in passing 
but in contact with mercury, very myste- to the state of a hydruret, absorbed 3( times 
lious phenomena occur. If a globule of its volume of hydrogen. The ammoniacal 
mercury be surrounded with a little water of bydruret of mercury and potassium may 
ammonia, or placed in a little cavity in a exist by itself; but as soon as we attempt to 
piece of sal ammoniac, and then subjected to separate or oxidize the potassium^ its other 
the voltaic power by two wires, the negative constituent principles also separate. Hence 
touching the mercury, and the positive the this hydruret is speedily decomposed by the 
ammoniacal compound, the globule is in- air, by oxygen gas, and in general by all bo- 
stantly covered with a circulating film, a dies that act upon potassium. It is even 
white smoke rises from it, and its volume affected by mercury, so that, in treating it 
enlarges, whilst it shoots out ramifications of with this metal, we may easily determine the 
n semi-soUd consistence over the salt. Hie relative quantity of ammonia and hydrogen 
amalgam has the consistence of soft butter, which it contains. We need only for this 
and may be cut with a knife. Whenever the purpose take up the interior parts of the by** 
electrisation is suspended, the crab-like fibres druret with a little iron spoon, fill up with it 
jvtract towards the central mass, which soon, a little glass tube already nearly full of mer- 
by the constant formation of white saline cury, and closing this with a very dry stop- 
films^ resumes its pristine globular shape and per, invert it in mercury equally dry. The 
sise. The enlargement of volume seems to hydruret will rise to the upper part of the 
amount occasionally to ten times that of the tube, will be decomposed, especially by a 
mercury, when a small globule is employed, slight agitation, and will give out hydrogen 
Sir H. Davy, Beraelius, and MM. Gay Lus- and ammonia in the ratio of ] to 2.5. 
nc and Thenard, have studied this singular The mere ammoniacal bydrurets contain 
phenomenon with great care. They produc- but a very small quantity of hydrogen and 
ed Ihe very same substance, by putting an ammonia. By supposing that, in the am^- 
amalgam of mercury and potassium into the moniacal bydruret of mercury, the hydrogen 
moistened cupel of sal ammoniac It be- is to the ammonia in the same proportion as 
comes five or six times larger, assumes the in the ammoniacal hydruret of mercury and 
consistence of butter, whikt it retains its potassium, it will appear that the first ia 
jmetallic lustre. formed, in volume, of 1 of mercury, 3.47 

What takes place in these experiments ? hydrogen, and 8.67 ammoniacal gas, at the 

In the second case, the substance of metallic mean pressure and temperature of 30, and 

aspect which we obtain is an ammoniacal 60*' ; or in weight, of about 1800 parts of 

bydruret of mercury and potassium. There mercury, with 1 part of hydrogen, and 1 of 

ia formed, besides, muriate of potash. Con- ammonia. 

eequently a portion of the potassium of the M. HoUunder describes a production of 

amalgam decomposing the water, becomes ammonia, which, in the present state of our 

potash, which itself decomposes the muriate knowledge, seems equally mysterious as the 

of ammonia. Tlience result hydrogen and above experimental results. He mixed liver 

smmonia, which, in the nascent state, unite of sulphur and pure iron filings tc^ether, put 

to the undeoompoaed amalgam. In ^ first them into a covered crucible, and exposed 

experiment, the substance which, as. in the them to a high temperature. When the 

second, presents the metallic aspect, is only double sulphuret thus obtained was moisten- 

an ammoniacal hydruret of mercury : its for- ed with a little water, it disengaged abun- 

mation is accompanied by the perceptible dant vapours of ammonia, and continued to 

evolution of a certain quantity of chlorine at do so as long as it remained hot. 
the positive pole. It is obvious, therefore. Ammonia is not affected by a cherry-red 

that the salt is decomposed by the electricity, heat According to Guyton de Morveau, it 

The hydrogen of the muriatic add, and the becomes a liquid at about 40° — 0°> or at 

ammonia, both combine with the mercury, the freezing point of mercury ; but it is un- 

These bydrurets possess the following pro- certain whetlier the appearances he observed 

perties:*^ may not have been owing to hygrometric 

Their sp. gravity is in general below 3.0 : water, as happens with chlorine gas. The 

exposed for some time to the temperature of ammoniacal liquid loses its pungent smell as 

31^ F. they assume conaiderable hardness, its temperature sinks, till at —-50° it gelati- 

and crystallize in cubes, which are often as nizes, if suddenly cooled ; but if slowly cooU 

beautiful and large as those of bismuth* ed, it crystallizes. 

Ether and alcohol instantly destroy these Oxygen, by means of electricity, or a mere 
amalgams, exciting a brisk effervescence with red heat, resolves ammonia into water and 
them, and reproducing the pure mercurial nitrogen. When there is a considerable ex- 
globule. These amalgams are slightly per- cess of oxygen, it acidifies a portion of the 
maneot in the air, if unitisturbed ; but the nitn^n into nitrous acid, whence many falla- 
kasfe agitation b fatal to. their existence, cies in analysis have arisen. Chlorine and 



AMMONIA. 



162 



AMMONIA. 



ammoiiia exercise so powerftil an action on 
each odier, that when mixed suddenly, a sheet 
of white flame pervades them. The simplest 
way of making this fine experiment^ is to in- 
vert a matrass, with a wide mouth and conical 
neck, over another with a taper neck, contain- 
ing a miiture of sal ammoniac and lime, 
heated by a lamp. As soon as the upper ves- 
sel seems to be full of ammonia, by the over- 
flow of the pungent gas, it is to be cautiously 
lifted up, and inserted in a perpendicular di- 
rection into a wide-mouthed glass decanter or 
flask filled with chlorine. On seizing the two 
vessels thus joined with the two hands covered 
with gloves, and suddenly inverting them, like 
a sand-glass, the heavy chlorine and light 
ammonia, rushing in opponte directions, unite 
with the evolution of flame. As one volume 
of ammonia contains, in a condensed states 
one and a half of hydrogen, which requires 
fisr its saturation just one and a half of chlo- 
rine, this quantity should resolve the mixture 
kito muriatic acid and nitrogen, and thereby 
give a ready analysis of the alkaline gas. If 
the proportion of chlorine be less, sal ammo- 
niac and nitrogen are the results. The same 
thing happens on mixing the aqueous solu- 
tions of ammonia and chlorine. But if large 
bubbles of chlorine be let up in ammoniacal 
water of moderate strength, luminous streaks 
are seen in the dark to pervade the liquid, 
and the same reciprocal change of the ingre- 
dients is effected. 

MM. Gay Lussac and Thenard state, that 
when three parts of ammoniacal gas and one 
of chlorine are mixed together, they condense 
into sal ammoniac, and azote equal to 1-lOth 
the whole volume is given out. This result 
is at variance with tiieir own theory of vo- 
lumes. 

Three of ammoniacal gas consist of 4^^ hy- 
drogen, and 1 ( nitrogen in a condensed state : 
I of chlorine seizes 1 of hydrogen to form 2 
of muriatic add gas, which precipitate with 2 
of ammonia, in a pulverulent muriate. But 
the 3d volume of ammonia had parted with 
1 volume of its hydrogen to the chlorine, and 
another half-volume of hydrogen will unite 
with 0. 166 of a volume of nitrogen, to form 

= 0.33 of redundant ammonia, while 

0.33 of a volume of nitrogen is left unem- 
ployed. Hence 2-3ds of a volume, or ]-6th 
of the original bulk of the mixed gases, ought 
to remain ; consisting of equal parti of am- 
monia and nitrogen, instead of 1-1 0th of 
azote, as the French chemists state. 

Iodine has an analogous action on ammo- 
nia,— seizing a portion of its hydrogen to form 
hydriodic add, whence hydriodate of ammonia 
results ; while another portion of iodine unites 
vrith the liberated nitrogen, to form the explo- 
sive pulverulent iodide. 
, Cyanogen and ammoniacal gas begin to act 
trpon each other wheneverthey come into con- 



tact, but some hours are requisite to render the 
efiect complete. They unite in the propoiw 
tion nearly of 1 to If* forming a oompoand 
which gives a dark orange-brown colour to 
water, but dissolves in only a very small quan- 
tity of water. The solution does not produce 
Prussian blue with the salts of iron. 

By transmitting ammoniacal gas through 
charcoal ignited in a tube, prussic or hydio*> 
cyanic add is formed. 

' T%e action of the alkaline metals on gase^ 
ous ammonia is very curious. When potas:. 
slum is fused in that gas, a very fusible olive* 
green substance, consisting of potassium, 
nitrogen, and ammonia,' is formed; and a vo^ 
lume of hydrogen remains, exactly equal to 
\rbat would result from the action on water of 
the quantity of potassium employed. Hence^ 
according to M. Thenard, the ammonia is 
divided into two portions. One is decom- 
posed, so that its nitrogen combines with the 
potassium, and its hydrogen remains free^ 
whilst the other is absori>ed in whole or in 
part by the nitroguret of potassium. Sodium 
acts in the same manner. Tbe olive substance 
is opaque, and it is only when in plates of ex- 
treme thinness that it appears semitransparent. 
It has nothing of the metallic appearance ; it 
is heavier than water ; and on minute inspect 
tion seems imperfectly crystallized, "^^eii 
it is exposed to a heat progressively increased; 
it melts, disengages ammonia, and hydrogen, 
and nitrogen, in the proportions constituting 
ammonia; then it becomes solid, still pr». 
serving its green colour, and is converted into 
a nitroguret of potassium or sodium. Ex* 
posed to the air at the ordinary temperature^ 
it attracts only its humidity but not its oxy- 
gen, and is slowly transformed into ammoni- 
acal gas, and potuh or soda. It bums vivid- 
ly when projected into a hot crucible, or when 
heated in a vessel containing oxygen. Water 
and adds produce also suddm decomposition, 
with the extrication of heat Alkalis or al- 
kaline salts are produced. Alcohol likewise 
decomposes it with similar results. The 
preceding description of the compound of 
ammonia with potassium, as prepared by 
MM. Gay Lussac and Thenard, was contro- 
verted by Sir H. Davy. 

The experiments of this accurate chemist 
led to the conclusion, that the presence of 
moisture had modified their results. In prob^ 
portion as more precautions are taken to keep 
every thing absolutely dry, so in proportion 
is less ammonia regenerated. He seldom ob- 
tained as much as 1-1 0th of the quantity ab- 
sorbed ; and he never could procure hydro- 
gen and nitn^n in the proportions consti- 
tuting a mmon ia ; there was always an excess 
<^ nitrogen. The following experiment was 
conducted with the utmost nicety. 3^ gr. of 
potassium were heated in 12 cubic inches of 
ammoniacal gas; 7.5 were absorbed, and 3.2 
of hydraigen evolved. On distilling tl^e oltTOt 



Auy^omA.. 



153 



AMMONIA. 



colound flolid in a tube of platins, 9 cubictl 
incibas of gas were,giTen oft, and half a cu- 
bical inch nmained in the tube and adapters. 
Of the 9 cubical inches, l-dth of a cubical 
inch only wss ammonia : 10 measures of the 
permanent gas mixed with 7.5 of oxygen, and 
acted upon by the electrical spark, left a re- 
aiduum of 7.5. He infers that the results 
of the analysis of ammonia, by electricity and 
potassium, are the same. 

On the whole we may l^itimately infer, 
that there is something yet unexplained in 
these phenomena. Tlie potassium separates 
irom ammonia as much hydrogen as an equal 
wci^t of it would irom water. If two to- 
lumesof hydrogen be thus detached from the 
alkaline gas, the remaining volume, with the 
▼olume of nitrogen, will be left to combine 
with die potassium, forming a triple com- 
pound somewhat analogous to the cyanides,*^ 
a compound cap^le of condensing ammonia. 
For an account of a singular combination of 
ammonia, by which its volatility seems d^ 
atroyed, see Chlorine. 

When ammoniacal gas is transmitted over 
ignited wires of iron, copper, platina, &c it 
is decomposed completely, and the several 
metals, when thus treated, become extremely 
brittle. Iron, at the same temperature, de- 
composes the ammonia wMi double the r»> 
pidity that platinum does. At a high tem- 
perature, the protoxide of nitrogen decom- 
poses ammonia. 

MBC Savartand Deq)retx have lately shown, 
that when heated metals are subjected to this 
action of ammoniacal gas, the change of 
freight which they experience is considerable, 
in consequence of combining with some part 
of the ammonia. M. Desprets states, that 
the weight of iron is sometimes increased as 
much as 1 1.5 per cent in such an experiment, 
in consequence of the combination of nitro- 
gen with it. If the temperature applied be 
too high, the nitrogen is expelled, and the 
compound destroyed. 

C6pper, iron and platina, are diminished 
in density, after they have been employed in 
decomposing ammoniacal gas in an ignited 
tube. 

Of the ordinary metals, line is the only 
one which liquid ammonia oxidises and then 
dissolves. But it acts on many of the me- 
tsUic oxides. At a high temperature the gas 
deoxidises all those which are reducible by 
-hydrogen. The oxides soluble in liquid am- 
jnonia are,— 4be oxide of rinc, the protoxide 
and peroxide of copper, the oxide of silver, 
.the third and fourth oxides of antimony, the 
oxide of tellurium, the protoxides of nickel, 
cobalt and iron, the peroxide of tin, mercury, 
gold, and platinum. Hie first five are very 
soluble, tlie rest less so. These combinations 
can be obtained by evaporation, in the dry 
atate, only with copper, antimony, mercury, 
gold, pbumum, and. silvery the four^tstof 



which are very remarkable for their datomit- 
ing property. See the particular metals. 

All the adds are susceptible of combiniag 
with ammonia, and they almost all form with 
it neutral compounds. M. Gay Lussac made 
the important discovery, that whenever the 
acid is gaseous, its combination with ammo- 
niacal gas takes place in a simple ratio of de^ 
terminate volumes, whether a neutral or a 
subsalt be formed. 

AMMONIACAL SALTS have the fol- 
lowing general charactera :— 

IsT, When treated with a caustic fixed al- 
kali or earth, they exhale the peculiar smell 
of ammonia. 

2dt They are generally soluble in water, 
and crystalliable. 

3tlf They are all decomposed at a moderate 
red heat; and if the add be fixed, as the phos- 
phoric or boradc, the ammonia comes away 
pure. 

4itkj When they are dropped into a solu- 
tion of muriate of platina, a yellow predpi- 
tate falls. 

1. jicetate. This saline compound. vras 
formerly called the Spirit of Mindererus, who 
introduced it into medicine as a febrifuge 
sudorific. By saturating a pretty strong acetic 
acid with subcArbonate of ammonia, endosing 
the liquid under the receiver of an air-pump^ 
along with a sauoerful of sulphuric add, and 
exhausting the air, the salt will concrete in 
adcular crystals, which are nearly neutral 
It may also be made very conveniently, by 
mixing hot saturated solutions of acetate c^ 
lead, and sulphate of ammonia, taking 100 
of the first salt in iU ordinary state to 34i.4 
of the second, well dried at a heat of 212^. 
Or even muriate of ammonia vrill answer in 
the proportion of 27.9 to 100 of the acetate. 
Acetate of ammonia has a cooling sweetish 
taste. • It is deliquescent, and volatile at all 
temperatures; but it sublimes in the solid 
state at 250^^. It consisto of 75^ of dry acetic 
acid, and 24^ ammonia. When intended for 
medidne, it should always be prepared from 
pure acetic add and subcarbonate of am- 
monia. 

Arteniaie of ammonia may be formed by 
saturating the arsenic add with nmmmiiy^ 
and evaporating the liquid. Crystals of a 
rhomboidal prismatic form are obtained. A 
binarseniate may also be made by using an 
excess of add. At a red heat, the ammonia 
of both salta is decomposed, and the add is 
reduced to the metallic state. Under the !«. 
spective adds, an account of several ammonia- 
cal salto will be found. As the muriate, how- 
ever, constitutes an extensive manufiicture^ 
we shall enter here into some additional de- 
tails concerning ita production. 

Sal ammoniac was originally fabricated in 
Egypt The dung of camels and other ani- 
mals constitutes the chief fuel used in that 
country. The ^oot Is careftilly coUeetedL 



AMMONIA. 



IM 



AMYGDALOID. 



Gkbular gUot tcswIs, about a Ibot in dift- 
meier, arc filled within a few inches of their 
mouth with it, and are then «rnuiged in an 
oblong furnace, where they are exposed to a 
beat gradually increased. The upper part 
of the glass balloon stands out of the furnace^ 
and is kept rehuaveiy cool by the air. On 
the third day the operation is completed, at 
which time they plunge an iron rod occasion- 
ally into the mouths of tlie glebes, to prevent 
them from closing up, and thus endanger the 
bursting of the glass. 

The fire is allowed to go out; and on 
breaking the cooled globes, their upper part 
is found to be lined with sal ammoniac in 
hemispherical lumps, about 2^ inches thick, 
of a greyish-white colour, semitransparent, 
and possessed of a d^ree of elasticity. 26 
pounds of sooL yield 6 of sal ammoniac The 
ordinary mode of manufacturing sal ammo- 
niac in £urope, is by combining with muri- 
atic acid the ammonia resulting from the 
igneous decomposition of animal matters in 
close vessels. Cylinders of cast-iron, fitted 
up as we have described under Acetic Acu), 
are charged with bones, horns, paringsof bides, 
and other animal matters ; and being exposed 
to a full red heat, an immense quantity of an 
impure liquid carbonate of ammonia distils 
ever. Mr Minish contrived a cheap method 
cf converting this liquid into sal ammoniac. 
He digested it with pulverized gypsum, or 
limply made it percolate through a stratum 
of bruised gypsum ; whence resulted a liquid 
sulphate of ammonia, and an insoluble car- 
bonate of lime. The liquid, evaporated to 
dryness, was mixed with muriate of soda, 
put into large glass balloons, and decomposed 
by a subliming heat Sal ammoniac was 
found above in its characteristic cake, while 
■nlphate of soda remained below. 

M. Leblanc of St Denis, near Fsris, in- 
vented another method of much ingenuity, 
which is described by a commission of emi- 
nent French chemists in tlie 19th volume of 
the JnttaUu de Chinde^ and in the J»iurnal 
de Piiysiqfte for the year 1794. He used 
tight brick kilns, instead of iron cylinders, 
for holding the materials to be decomposed. 
Into one he put a mixture of common salt 
and (h1 of vitriol ; into another, annual mat- 
ters. Heat extricated from the first muriatic 
acid gas, and from the second ammonia; 
which bodies being conducted by their re^ 
■poctive flues into a third chamber lined with 
lead, and containing a stratum of water on 
its bottom, entered into combination, and 
precipitated in solid sal ammoniac on the roof 
and ^es, or in liquid at the bottom. 

In the 20th volume of the Annates, a plan 
for employing bittern or muriate of magnesia 
to furnish the acid ingredient is described. 
An ingenious process on the same principles 
was some time ago commenced at Borrow- 
aioanneBS in Scotland, by Mr Astley. He 



imbued in a alove-rioomt heated by brick fiuoa, 
parings of skins, horns, and other animal 
matters, with the muriate of magnesia, or 
mother water of the sea-salt works. The 
matters tlius impregnated and dried were 
subjected in a close kiln to a red heat, when 
the sal ammoniac vapour sublimed, and was 
condensed dther in a solid form into an 
acQoining chamber or chimney, or dse into a 
stratum of water on its bottom. Muriate of 
magnesia at a red beat evolves muriatic add 
gas ; an evolution probably aided in the pr»> 
sent case by the affinity of ammonia. 

From coal soot likewise a considerable 
quantity of ammonia, in the state of carbo- 
nate and sulphate, may be obtained, either by 
sublimation or lixiviation with water. These 
ammoniacal products can afterwards be readily 
converted into the muriate, as above describ- 
ed. M. Leblanc used a kettle or eolipile 
for projecting steam into the leaden chamber, 
to promote the combination. It is evident, 
that the exact neutralisation essential to aal 
ammoniac might not be hit at first in these 
operations; but it could be afterwards effect- 
ed by the separate addition of a portion of 
alkaline or acid gas. As the mother waters 
of the Cheshire salt works contain only 3{ 
per cent of muriate of magnesia, they are not 
suitable, like those of sea-salt works, for the 
above manufacture. See Salt. 

AMMONIAC (GUM). Tliis is a gum 
resin, which consists, according to Bracon* 
not, of 70 resin, 18.4 gum, 4.4 glutinous 
matter, 6 water, and 1.2 loss in 100 parts. 
It forms a milky solution with water ; is paiw 
tially soluble in alcohol; entirely in ether, 
nitric acid, and alkalis. Sp. gr. 1.200. It 
has rather a heavy smell, and a bitter-sweet 
taste. It is in small agglutinated pieces of 
a yellowish-white colour. It is usc^ in in»> 
didne as an expectorant and antispasmodic. 
AMMONITEa lliese petrifactions, 
which have likewise been distinguislied by 
the name of cornua ammonUf and are called 
tnake^itimes by the vulgar, consist chiefly of 
lime-stone. They are found of all sixes, 
from the breadth of half an inch to more 
than two feet in diameter; some of them 
rounded, others greatly compressed, and 
lodged in different strata of stones and claySk 
"Diey appear to owe their origin to shells of 
tlie nautilus kind. 

AMOMUM. See Fdiento. 

A MP£L I TE. The aluminous ampelite 
is the alum slate, and the graphic^ the gni»> 
phic slate. 

AMPHIBOLE. See Hornblende, and 

ACTYNOLITK. 

AMPHIBOLITE& In geology, trap 
rocks, the basis of which is amphibole or 
hornblende. 

AMPHIGENE. See VEmmAN. 

AMYGDALOID. A compound mi. 
neraly consiatiog of spheroidal partides of 



ANALYSIS. 



U»5 



ANALYSIS. 



€■ lithflBMi^gfy gfcm Mftby cue spsP) ■ 
BtMtltei imbedded in a basis of fine-graioed 
grcemitone^ or wacke, containing sometimes 
also crjstaJs of hornblende. 

AMYLINE or AMYDINE. Saussure 
exposed a solution of starch in tweWe times 
its weight of water to the air, in a shallow 
capsule, for two years. It had then become 
a grey liquid, covered with mould, free from 
smell, anid without action on vegetable blue 
colours. The starch had lost nearly one- 
lonrth of its weight, and the remainder was 
converted into the following substances :<^1. 
Sugar, amounting to one-half of the starch ; 
2, Gum, or a substance analogous to it, ob- 
tained by roasting starch; 3. Amyline; 4. 
Starchy lignine ; 5. Lignine mixed with char- 
coal. AmyUne is intermediate between gum 
sod starch. It is soluble in boiling water, 
and the solution affords by evaporation a pale 
semitransparent Inittle substance, insoluble 
in alcohol, but soluble in ten times its weight 
of cold water, and to any extent in water at 
I44r^. The solution becomes a white paste 
with subacetate of lead. With iodine it be- 
comes blu& It is precipitated by baryta 
water, but not by lime water, potash, soda, 
or^la.~PAi^ Trant^ 1819. 

ANACARDIUM, cashew nut, or maric- 
ing nut. At one extremity of the fruit of 
the cashew tree is a flattish kidney-shaped 
nut, between the rind of which and the thin 
outer shell is a small quantity of a red, thick- 
ish, inflammable^, and very caustic liquor. 
This liquor forms an useful marking ink, as 
any thii^ written on linen or cotton with it 
ia of a brown colour, which gradually grows 
blacker, and is very durable. 

ANALCIME. Cubic zeolite. This mi- 
neral is generally found in aggregated or 
cubic crystals, whose solid angles are replaced 
by three planes. Kztemal lustre between 
vitreous and pearly ; fracture flat concboidal ; 
colours, white, grey, or reddish ; translucent. 
From the becoming feeUy electrical by heat 
it has got the name analcime. Its sp. gr. is • 
less than 2.& It consists of 58 silica, 18 
alumina, 2 lime, 10 soda, 8^ water, and ^ 
loss, in 100 parts. It is found in granite, 
gneiss, trap rocks and lavas, at Calton Hill 
Edinburgh, at Talisker in Sky, in Dumbaiv 
tonshire, in the Hartz, Bohemia, and at the 
Ferroe Islands. The variety found at Som- 
ma has been called sarcolite, from its flesh 
colour. 

ANA L YSI S. Chemical analysis consists 
of a great variety of operations, performed 
for the purposes of separating the component 
parts of bodies. In these operations the 
most extensive knowledge of such properties 
of bodies as are already discovered must be 
applied, in order to produce simplicity of 
dfoct, and certainty in the results. Chemi- 
cal analysis cannot be executed with success 
bf «ne who is not in p osi —i o n of a consid- 



erable number of dmple substances in a Male* 
of great purity, which, from thenr effects, aia< 
called reagents. The word analysis is applied 
by chemists to denote that series of operations! 
by which the component parts of bodies aro 
determined, whether they be merely separa- 
ted, or exhibited apart from each other ; or 
whether these distinctive properties be ex- 
hibited by causing them to enter into new 
combinations. The forming of new combi- 
nations is called synthesis ; and, in the chemi- 
cal examination of bodies, analysis or separa- 
tion can scarcely ever be effected, without 
synthesis taking place at the same time. 

As most of the improvements in the science 
of chemistry consist in bringing the art of 
analysis nearer to perfection, it is not easy to 
give any other rule to the learner, than the 
general one of consulting and remarking tho 
processes of the best chemists, such as Scheele, 
Bergman, Klaproth, Kir wan, Vauquelin, and- 
Berzelius. The bodies which present them- 
selves more IVequently for examination than 
others are, minerals, and mineral waters. In 
the examination of the former, it was the 
habit of the earlier chemists to avail them- 
selves of the action of fire, with very few 
humid processes, which are such as might bo 
performed in the usual temperature oS the 
atmosphere. Modem chemists have improv- 
ed the process by fire, by a very extensive use 
of the blowpipe (see Blowpipe); and have 
succeeded in determining the component parta 
of minerals to great accuracy in the humid 
way. For the method of analyzing mineral 
waters, see Waters (Mineral); and for 
the analysis of metallic ores, see Ores. 

Several authors have written on die ex-< 
amination of earths and stones. 

The^r<< step in the examination of indu- 
rated earths or stones, is somewhat different 
from that of such as are pulverulent Their 
specific gravity should first be examined ; also 
their hardness, whether they will strike fira 
with steel, or can be scratched by the nail, 
or only by crystal, or stones of still greater 
hardness ; also their texture, perviousness to 
light, and whether they be manifestly homo- 
geneous or compound species, &c 

2d, In some cases, we should try whether 
they imbibe water, or whether water can ex- 
tract any thing from them by ebullition or 
digestion. 

dJ, Whether they be soluble in, or effer- 
vesce with acids, before or afWr pulverization ; 
or whether decomposable 'by boiling in a 
strong solution of potash, &c., as gypsums 
and ponderous spars are. 

4<A, Whether they detonate with nitre. 

bthf Whether they yield the fluoric acid by 
distillation with sulphuric add, or ammoimv 
by distilling them with potash. 

SlA, Whether they be ftisible per te with 
ablowpipe^ and howthey areaffiecledby soda. 



ANALYSIS. 156. ANALYSIS. 

faonxy.and microooaiiic nit; .wad whether, endof UieeTapoiatioin,itassuine8ageladiioiis< 

they decrepitate when gradually heated. coiuiatence. At this period it must be stirred * 

7th, Stones that melt per u with the blow- frequently with a platinum spatuU or glass . 

pipe are certainly compound, and contain at rod, to promote the disengagement of the • 

least three species of earth, of which the cal- muriatic acid gas. After this, the heat may 

careous is probably one ; and if they give fire be raised to fully 212° F. for a few minutes, 

with steel, the siliceous is probably another. • Hot water b now to be poured on in consi^ 

The general process prescribed by the derable abundance, which dissolves every- 

celebrat^ Vauquelin, in the 30th volume of thing except the silica. By filtration, this 

the Annates de Qiinde^ is the clearest which earth is separated from the liquid ; and being 

has yet been offered to the chemical studenL edulcorated with hot water, it is then dried. 

If the mineral be very hard, it is to be ignited, and weighed. It constitutes a fine 

ignited in a covered crucible of platinum, and white powder, insoluble in acids, and feeling • 

then plunged into cold water, to render it gritty between the teeth. If it be coloured, 

brittle and easily pulverizable. The weight a litUe dilute muriatic acid must be digested 

should be noted before and after this opera- on it, to remove the adhering metallic par- 

tion, in order to see if any volatile matter has ticles, which must be added to the first, solu- 

been emitted. For the purpose of reducing tion. This must now be reduced by evapo- • 

stones to an impalpable powder, little mortars ration to tlie bulk of half a pint Caibonate . 

of highly hardened steel are now made, con- of potash being then added till it indicates - 

aisting of a cylindrical case and pestle. A alkaline excess, the liquid must be made to 

mortar of agate is also used for subsequent boil for a little. A copious precipitation of. 

levigation. About ten grains of the mineral the earth and oxides is thus produced. The - 

should be treated at once ; and after the whole whole is thrown on a filter, and after it is so 

100 grains have been reduced in succession drained as to assume a semi-solid consistence, 

to an impalpable powder, they should be it is removed by a platinum blade, and l>oiled' 

weighed, to find what increase may have been in a capsule for some time, with solution of 

derived from the substance of the agate. . pure potash. Alumina and glucina are thus - 

This addition may be regarded as silica. dissolved, while the other earths and the me- 

Of the primary eartlis, only four are usually tallic oxides remain. , 

met with in minerals, viz. silica, alumina* This alkalino-earthy solution, separated 

magnesia, and lime, associated with some me- from the rest by filtration, is to be treated 

tallic oxides, which are commonly iron, man-, with an excess of muriatic acid ; after which- 

ganese, nickel, copper, and chromium. carbonate of ammonia being added also in 

If neither acid nor alkali be expected to be excess, the alumina is thrown down, while the 

present, the mineral is mixed in a silver cm- glucina continues dissolved. The first eaitb 

cible, with thrice its weight of pure potash separated by filtration, washed, dried, and 

and a little water. Heat is gradually applied ignited, gives the quantity of alumina. The 

to the covered crucible, and is finally raised nature of this nuiy be further demonstrated, 

to redness ; at which temperature it ought to by treating it with dilute sulphuric add and 

be maintained for an hour. If the mass, on sulphate of potash, both in equivalent quan- 

inspection, be a perfect glass, silica may here- titles, when the whole will be converted into 

gaided as the cliief constituent of the stone ; alum. (See Alum. ) The filtered liquid will 

but if the vitrification be very imperfect, and deposit its glucina, on dissipating the am- 

the bulk much increased, alumina may be monia by ebullition. It is to be separated 

supposed to predominate. A brownish or by filtration, to be washed, ignited, and- 

dull green colour indicates the presence of weighed. 

iron ; a bright grass-green, which is imparted The matter undissolved by the digestion of 
to water, Uiat of manganese ; and from a the liquid potash, may consist of lime, mag- 
greenish-yellow, chromium may be expected, nesia, and metallic oxides. Dilute sulphuric 
The crucible, still a little hot, being first acid must be digested on it for some time, 
viped, is put into a capsule of porcelain or The solution is to be evaporated to dryness* 
platinum; when warm distilled water is and heated, to expd the excess of acid. Tlie 
poured upon the alkaline earthy mass, to de- saline solid matter being now diffused in a 
tach it from the crucible. Having transferred moderate quantity of water, the sulphate o£ 
the whole of it into the capsule, muriatic acid magnesia will be dissolved, and, along with 
is poured on, and a gentle heat applied, if the metallic sulphates, may be separated from- 
necessary, to accomplish its solution. If the the sulphate of lime by the filter. The latter 
liquid be of an orange-red colour, we infer being washed with a little water, dried, ig- 
thepresenceofiron; if of agolden yellow, that nited, and weighed, gives, by the scale of 
of diromium ; and if of a purplish-red, that of equivalents, the quantity of lime in the mine- 
manganese. The solution is next to be eva-. nd. The magnesian and metallic solution, 
poratod to dryness on a sand bath, or over a being diluted with a large quantity of water, 
Vunp, taking care so to regulate the heat that is to be treated with bicarbonate of potash, 
no pariddes be thrown out Towards the vliich will precipitate the nickfil, .iron, and> 



ANALYSIS. 



157 



ANALYSia 



^ramiUiD, but retain the magncua and dian-' 
ganese, by the excess of carbonic add. Hy- 
droaulphuret of potash will throw down the 
■umganese from the magnesian solution. 
Hie addition of pure potash, aided by gentle 
ebullition, will then precipitate the magnesia. 
The oxide of manganese may be freed from 
the sulphuretted hydrogen, by ustulation. 

The mingled metallic oxides must be di- 
gested with abundance of nitric add, to aci- 
dify the chromium. The liquid is next treated 
with potash, which forms a soluble chromate, 
while it throws down the iron and nickel. 
The chromic acid may be separated from the 
potash by muriatic add and digestion with 
beat, washed, dried till it become a green 
oxide, and weighed. Hie nickel is separated 
from the iron, by treating their solution in 
muriatic add with water of ammonia. The 
latter oxide, which falls, may be separated by 
the filter, dried and wdghed. By evaporat- 
ing the hquid, and exposing the dry residue 
to a moderate heat, the ammoniacal salt will 
sublime^ and leave the oxide of nickel behind. 
The whole separate weights must now be col- 
lected in one amount, and if they constitute 
a sum within two per cent of the primitive 
weight, the analysis may be regarded as giving 
a satisfactory account of- the composition of 
the mineral. But if the defidency be con- 
siderable, then some voktile ingredient, or 
some alkali or alkaline salt, may be suspected. 

A portion of the mineral broken into small 
fragments, is to be ignited in a porcelain re- 
tort, to which a refrigerated recdver is fitted. 
The water, or other volatile and condensable 
matter, if any be present, will thus be ob- 
tained. Bat if no loss of weight be sustained 
by ignilion, alkali, or a volatile acid, may be 
looked for. The Utter is usually the fluoric. 
It may be expelled by digestion with sulphu- 
ric add. It is exactly characterixed by its 
property of corroding glass. 

Beside this general method, some others 
may be used in particular cases. 

Thus, to discover a small proportion of 
alumina or nuignesia in a solution of a large 
quantity of lime, pure ammonia may be ap- 
plied, which will precipitate the alumina or 
magnesia (if any be), but not the lime. Dis- 
tilled vinegar applied to the precipitate will 
discover whether it be alumina or magnesia. 

2d/y, A minute portion of lime or bar3^ 
in a solution of alumina or magnesia, may 
be discovered by the sulphuric add, which 
predpitates the lime and baryta : the solution 
should be dilute, else the alumina also would 
be predpiuted. If there be not an excess of 
add, the oxalic add is still a nicer test of lime : 
100 grains of gypsum contain about 33 of 
lime ; 100 grains of sulphate of baryta con- 
tain 66 of baryta ; 100 grains of oxalate of 
Imw contain 43.8 of lime. The insolubiUty 
of. sulphate of baryta in 500 times its wdgbt 
1^ boiling water, suffidcntly distinguishes it 



From th^se data the quantities are easily iiU* 
vestigated. 

3dfy, A minute proportion of aluz|iina in 
a large quantity of magneda may be dia- 
covered, dther by predpitating the whole, 
and treating it with distilled vinegar ; or by 
heating the solution nearly to ebullition, and 
adding more carbonate of magnesia until the 
solution is perfectly neutral, which it never is 
when alumina is contained in it, as this re- 
quires an excess of add to keep it in solution. 
By these means the alumina is predpitated in 
the state of embryon alum, which contains 
about half its wdgbt of alumina; (or, fl(fr 
greater exactness, it may be decon^posed by 
boiling it in volatile alkidi). After the pre- 
dpitation the solution should be largely di- 
luted, as the sulphate of magnesia, which re- 
mained in solution while hot, would predpi- 
tate when cold, and mix with the embryon 
alum. 

iiA/y, A minute portion of magnesia in a 
large quantity of alunu'na is best separated by 
predpitating the whole, and treating the pr&- 
dpitate with distilled vinegar. 

Lasllifi Lime and baryta are separated by 
predpitating both with the sulphuric add, 
and evaporating the solution to a small com- 
pass, pouring off the liquor, and treating the 
dried predpitate with £4X) times its wdgbt of 
boiling water : what remains undissolved is 
sulphate of baryta. 

The inoonveniendes of employing much 
heat are obvious, and M. Lowita informs us 
that they may be avoided without the least 
disadvantage. Over the flame of a spirit 
lamp, that will hold an ounce and a half, and 
is placed in a cylindrical tin furnace, four 
inches high and three in diameter, with aiiv 
holes, and a cover perforated to hold the cru- 
dble, he boils the stone prepared as directed 
above, stirring it frequently. His crudble^ 
which, as well as the spatula, is of very fine 
silver, holds two ounces and a half, or three 
ounces. As soon as the matter is bdled dry, 
he pours in as much hot water as he used at 
first ; and this he repeats two or three times 
more, if the refractoriness of the fossil require 
it. Large tough bubbles arising during the 
boiling, are in general a sign that the process 
will be attended with success. Even the 
sapphire, though the most refractory of all 
M. Lowiu tried, was not more so in this* 
than in the dry way. 

Sir H. Davy observes, that boradc add is 
very useful in analysing stones that contain a 
fixed dkali ; as its attraction for the different 
earths at the heat of ignition is considerable^ 
and the compounds it forms with them are 
easily decomposed by the mineral adds dis- 
solved in water. His process is as follows : 
Let 100 grains of the stone to be examined. 
be reduc^ to a fine powder, mixed with 200 
grains of boradc acid, and fused for about, 
half an hour at a strong red heat in a cradble 



ANALYSIS. 



156 



ANALYSIS. 



of pktiiui or silver. Digest the fused mass in 
«) ounce and half of nitric add, diluted witli 
seven or eigiit times the quantity of water, 
till the whole is decomposed ; and then eva- 
porate the solution till it is reduced to an 
ounce and half, or two ounces. If the stone 
contained silei, it will separate in this process, 
and must be collected on a filter, and edulco- 
rated with distilled water to separate the sa- 
line matter. The fluid, mixed with all the 
water that has been passed through the filter, 
being evaporated till reduced to about half a 
pint, is to be saturated with carbonate of am- 
monia, and boiled with an excess of this salt, 
till all that will precipitate has fallen down. 
The earths and metallic oxides being sepa- 
rated by filtration, mix nitric acid with the 
clear fluid till it has a strongly sour.taste, and 
then evaporate till the boracic acid remains 
free. Filter the fluid, evaporate it to dryness, 
and expose it to a heat of 460° F., when the 
nitrate of ammonia will be decomposed, and 
the nitrate of potash or soda will remain in the 
vessel. The earths and metallic oxides that 
remained on the filter, may be distinguished 
by the common processes. The alumina may 
be separated by solution of potash, the lime by 
sulphuric acid, the oxide of iron by succinate 
of ammonia, the manganese by hydrosulphuret 
of potash, and the magnesia by pure soda. 

Lately, carbonate or nitrate of baryta, and 
carbonate with nitrate of lead, have been in- 
troduced into mineral analysis with great ad- 
vantage, for the fluxing of stones that may 
contain alkaline matter. See Mr Children's 
Translation of M. Hienard's volume on 
analysis. 

' M. Berthier shows, that the ready fusion 
of certain atomic mixtures of salts, may be 
applied to the analysis of siliceous minerals 
by alkaline carbonates, aided by a spirit lamp. 
A mixture of five parts of cariK>nate of pot- 
assa, and four parts of carbonate of soda, is 
so fusible, that between 200 and 300 grains 
may be rendered perfectly liquid by a spirit 
flame. If sand be added to the mixture, 
there is an effervescence as lively as if add 
had been added. The operation should, 
therefore, commence with the mixture of the 
carbonates and the mineral. In this manner, 
insoluble quantities of felspar may be readily 
decomposed by the heat of a spirit of wine 
lamp. 

M. Berzelius has very recently employed 
fluoric add in a most ingenious manner for the 
analysis of siliceous minerals. In extracting 
lithta, for example, from tripbane or spodu- 
mene, he mixes the mineral, in powder, with 
twice its weight of pulverised fluor-spar, and 
with sulphuric add ; he then heats the mix- 
ture so that the fluoric add shall carry off the 
silica in the form of fluosilidc add gas, and 
be afterwards separates the sulphate of lithia 
from the residuary matter by solution. 

Under the head of mineral analysis, nothing 



is of so much general importance as the eia- 
mination of soils, with a view to- the improve- 
ment of such as are less productive, by sup- 
plying the ingredients they want in due 
proportions to increase their fertility. To 
Lord Dundonald and Mr Kirwan we are 
much indebted for their labours in this field 
of inquiry ; but Sir H. Davy, assisted by the 
labours of these gentlemen, the facts and ob- 
servations of Mr Young, and his own skill 
in chemistry, having given at large, in a 
manner best adapted for the use of the prac- 
tical farmer, an account of the methods to be 
pursued for this purpose, we shall here copy 
them. 

The substances found in soils are certain 
mixtures or combinations of some of the 
primitive earths, animal and vegetable matter 
in a decomposing state, certain saline com- 
pounds, and the oxide of iron. These bodies 
always retain water, and exist in very different 
proportions in different lands, and the end of 
analytical experiments is the detection of thdr 
quantities and mode of union. 

The earths commonly found in soils are 
prindpally silex, or tlie earth of flints ; alu- 
mina, or the pure matter of clay ; lime, or 
calcareous earth ; and magnesia : for the cha- 
racters of which see the anides. Silex com- 
poses a considerable part of hard gravelly 
soils, hard sandy soils, and hard stony lands. 
Alumina abounds most in clayey soils, and 
clayey loams ; but even in the smallest par- 
ticles of these soils it is generally united with 
silex and oxide of iron. Lime always exists 
in soils in a state of combination, and chiefly 
with carbonic add, when it is called carbonate 
of lime. This cariionate in its hardest state is 
marble ; in its softest, chalk. Lime united 
with sulphuric acid is sulphate of lime, or 
gypsum ; with phosphoric add, phosphate of 
lime, or the earth of bones. Carbonate of 
lime, mixed with other substances, composes 
chalky soils and marls, and is found in soft 
sandy soils. Magnesia is rarely found in 
soils ; when it is, it is combined with carbonic 
add, or with silex and alumina. Animal 
decomposing matter exists in different states, 
contains much carbonaceous substance, vo- 
latile alkali, inflammable aeriform products, 
and carbonic add. It is found chiefly in 
lands lately manured. Vegetable decom* 
posing matter usually contains still more car- 
bonaceous substance, and differs from tlie 
preceding, prindpally, in not produdng vo- 
latile alkalL It forms a great proportion of 
all peats, abounds in rich mould, and is found 
in larger or smaller quantities in all lands. 
The saline compounds are few, and in small 
quantity : they are chiefly muriate of soda, 
or common salt, sulphate of magnesia, mu- 
riate and sulphate of potash, nitrate of lime^ 
and the mild alkalis. Oxide of iron, which 
is the same with the rust produced by ez-* 
posing iron to air and water, is found in all 



ANALYSIS. 



159 



ANALYSIS. 



but moit abundantly in red and yeUow 
dajfly and red and yellow siliceous sands. 

'Vhe instruments requisite for the analysis 
of soils are few. A pair of scales capable of 
bdding a quarter of a pound of common 8oil» 
and turning with a single grain when loaded : 
A set of weights, from a quarter of a pound 
troy to a grain : a wire sieve, coarse enough to 
let a pepper-corn pass through : an Argand 
lamp land stand : a few glass bottles, Hessian 
crucibles, and china or queen's ware evapo- 
rating bsoins : a Wedgwood pestle and mor- 
tar: some filters made of half a sheet of 
blotting paper, folded so as to contain a pint 
of liquid!, and greased at the edges : a bone 
knife; and an apparstus for collecting and 
measuring aeriform fluids. 

The reagents necessary are muriatic acid, 
sulphuric acid, pure volatile alkali dissolved 
in water, solution of prussiate of potash, 
soap lye, and solutions of carbonate of am- 
monia, muriate of ammonia, neutral cart>o- 
nate ot potash, and nitrate <»f ammonia. 

I. When the general nature of the soil of 
a field is to be ascertained, specimens of it 
should be taken from difierent places, two 
or three inches below the surface, and ez»- 
■lined as to the similarity of their properties. 
It sometimes happens, that on plains the 
whole of the upper stratum of the land is of 
the same kind, and in this case one analysis 
will be sufficienL But in vallejrs, and near 
the beds of rivers, there are very great dii&r- 
cocea, and it now and then occurs, that one 
part of a field is calcareous, and another part 
siliceous; and in this and analogous cases, 
the portions different from eadi other should 
be aiialysed separately. Soils when collect- 
ed, if they cannot be examined immediately, 
should be preserved in phials quite filled with 
them, and closed with ground glaiis stopples. 
The most convenient quantity for a perfect 
analysis is from two hundred grains to four 
hundred. It should be collected in dry wea- 
ther, and exposed to the air till it feels dry. 
Its specific gravity niay be ascertained, by 
introducing into a (rfiial, which will contain a 
known quantity of water, equal bulks of water 
and of the soil ; which may easily be done 
by pouring in water till. the phial is half full, 
aiid then adding the soil till the fluid rises 
to the mouth. The diffSnrence between the 
weight of the water and that of the soil, will 
give the result. Hius, if the bottle will con- 
tain four hundred grains of water, and gains 
two hundred grains when half filled with 
water and half with soil, the specific gravity 
of the soil will be 2 ; that is, it will be twice 
as heavy as water : and if it gained one hun- 
dred and sixty-five grains, its specific gravity 
would be 182d» water being 1000. It is of 
importance that the specific grarity of a soil 
Aottld be known, as it aflfords an indication 
of the quantity of animal and vegetable mat* 
ler it contains; these tubatances being alw^ps 



most abundant in the lighter soils. Tkb 
other physical properties of soils should like- 
wise be examined before the analysis is made^ 
as they denote, to a certain extent, their com- 
position, and serve as guides in directing the 
experiments. Thus, siliceous soils are gene- 
rally rough to the touch, and scratch glass 
when rubbed upon it; aluminous soils ad- 
here strongly to the tongue, and emit a 
strong earthy smell when breathed upon; 
and calcareous soils are soft, and much lesa 
adhesive than aluminous soils. 

2. Soils, when as dry as they can be made 
by exposure to the air, still retain a consider- 
able quantity of water, which adlieres with 
great ointinacy to them, and cannot lie driven 
off without considerable heat : and the first 
process of analysis is to free them from as 
much of this water as possible, without affect- 
ing their composition in other respects. This 
may be done by heating the soil for ten or 
twelve minutes in a china basin over an 
Argand lamp, at a temperature equal to 
30(M^ F. ; and if a thermometer be not used, 
the proper degree of heat may easily be ascer- 
tained by keeping a piece of wood in the basia 
in contact with iu bottom ; for as long as the 
colour of the wood remains unaltered, the beat 
is not too high ; but as soon as it begins to be 
charred, the process must be stopped. In 
several experiments, in which Sir U. Davy 
collected the water that came over at tbia 
degree of heat, he found it pure, without any 
sensible quantity of other volatile matter 
being produced. The loss of weight in this 
process must be carefully noted ; and if it 
amount to 50 grains in 400 of the soil, this 
may be considered as in the greatest degree 
absorbent and retentive of water, and will 
generally be found to contain a large pro- 
portion of aluminous earth. If the loss be 
not more than 10 or 20 grains, the land may 
be considered as slightly absorbent and re- 
tentive, and the siliceous earth as most abun- 
dant. 

S. None of the loose stones, gravel, or 
large v^etable fibres, should he separated 
from the soil, till the water is thus expelled ; 
for these bodies are oflen highly abMrbent 
and retentive, and consequently influence the 
fertility of the land. But after the soil has 
been heated as above, these should be sepa- 
rated by the sieve, after the soil has been 
gently bruised in a mortar. The weights of 
the vegetable fibres or wood, and of the 
gravel and stones, should be separately noted 
down, and the nature of the latter ascertain* 
ed : if they be calcareous, they will effervesce 
with acids; if siliceous* they will scratch 
glass ; if aluminous, they will be soft, easily 
scratched with a knifes and incapable of ef- 
fervescing with acids. 

4. Most soils, besides stones and gravely 
contain laiger or smaller proportions of sand 
of different degrees of finencis ; and the next 



ANALYSIS. 



160 



ANALTSia 



Operadon necenary is to separate this sand 
from the parts more minutely difided, such 
as clay, loam, marl, and vegetable and animal 
matter. This may be done sufficiently by 
mixing the soil well with water ; as the coarse 
sand will generally fall to the bottom in the 
space of a minute, and the finer in two or 
three : so that by pouring the water off after 
one, two, or three minutes, the sand will be 
for the most part separated from the other 
substances ; which, with the water containing 
them, must be poured into a filter. After 
the water has passed through, what remains 
on the filter must be dried and weighed, as 
must also the sand; and their respecdve 
quantities must be noted down* The water 
must be presenred, as it will coritain the saUne 
matter, and the soluble animal or vegetable 
matter, if any existed in the soil. 

5. A minute analysis of the sand thus se- 
parated is seldom or never necessary, and its 
nature may be detected in the same way as 
that of the stones and graveL It is always 
siliceous sand, or calcareous sand, or both 
together. If it consist wholly of carbonate 
of lime» it will dissolve rapidly in muriatic 
acid with effervescence; but if it consist 
partly of tliis and partly of siliceous matter, 
a residuum will be left after the acid has 
ceased to act on it, the acid being added till 
the mixture has a sour taste^ and has ceased 
to effervesce. This residuum is the siliceous 
part; which being washed, dried, and heated 
strongly in a crucible, the difference of its 
weight from that of the whole, will indicate 
the quantity of the calcareous sand. 

6. The finely divided matter of the soil is 
usually very compound in its nature: it 
sometimes contains all the four primitive 
earths of soils, as well as animal and vege- 
table matter ; and to ascertain the proportions 
6f these with tolerable accuracy, u the roost 
difficult part of the subject. The first pro- 
cess to be performed in this part of the ana- 
lysis, is the exposure of the fine matter of the 
ioil to the action of muriatic add. This 
acid, diluted with double its bulk of water, 
should bte poured upon the earthy matter in 
an evaporating basin, in a quantity equal to 
twice the weight of the earthy matter. Tlie 
mixture should be often stirred, and suffered 
to remain for an hour, or an hour and a half, 
before it is examined. If any carbonate of 
time, or of magnesia, exist in the soil, they 
will have been dissolved in this time by the 
acid, which sometimes takes up likewise a 
little oxide of iron, but very seldom any 
alumina. The fluid should be passed through 
a filter ; the solid matter collected, washed 
with distilled or rain water, dried at a modcu 
rate heat, and wdgbed. Its loss will denote 
the quantity of solid matter taken up. The 
washings must be added to the solution; 
whieh, if not sour to the taste, must be made 
so by the addition of fresh add ; and a little 



solution of prussiate of potadi must be tnixed 
with the liquor. If a blue predpitate Qccur^ 
it denotes the presence of oxide of iron, and 
the solution of the prussiate must be dropped 
in, till no further effect is produced. To 
ascertain its quantity, it must be collected on 
a filter in the same manner as the other solid 
predpitates, and heated red: the result will 
be oxide of iron. . Into the fluid freed from 
oxide of iron, a solution of carbonate pf 
potash must be poured, till all effervescence 
ceases in it, and till its taste and smell indi- 
cate a considerable excess of alkaline salt. 
The predpitate that falls down is carbonate 
of lime, which must be collected on a filter^ 
dried at a heat below that of redness, and 
afterwards weighed. The remaining fluid 
must be boiled for a quarter of an hour, when 
the magnesia, if there be any, will be pre- 
dpitated combined with carbonic add ; and 
its quantity must be ascertained in the same 
manner as that of the carbonate of lime. If 
any minute proportion of alumina should, 
from peculiar drcumstances, be dissolved by 
the add, it will be found in the predpitate 
with the carbonate of lime, and it may be 
separated from it by boiling for a few minutes 
with soap lye suffident to cover the solid 
matter : for this lye dissolves alumina, with- 
out acting upon carbonate of lime. Should 
the finely divided soil be sufficientiy calcare- 
ous to effervesce very strongly with adds, a 
simple method of ascertaining the quantity 
of carbonate of lime, suffidentiy accurate in 
all common cases, may be adopted. As car- 
bonate of lime in all its states contains a de- 
terminate quantity of add, which is about 
44 parts in a hui\dred by weight, the quanti- 
ty of this add given out during the efferves- 
cence occasioned by its solution in a stronger 
add, will indicate the quantity of carbonate 
of lime present. Thus, if you wdgh sepa- 
rately one part of the matter of the soil, and 
two parts of the add diluted with an equal 
quantity of water, and mix the add slowly in 
small portions with the soil, till it ceases to 
occasion any effervescence,— by wdghing the 
mixture, and the add that remains, you will 
find the quantity of carbonic add lost ; and 
for every four grains and half so lost, you 
will estimate ten grains of carbonate of lime. 
You may also collect the carbonic add in the 
pneumatic ajtparatut /or the analysit oftoUt^ 
described in the article Laboratory; and 
allow for every ounce measure of the carbonic 
add, two grains of carbonate of lime. 

7. The quantity of insoluble animal and 
vegetable matter may next be ascertained 
with sufficient precision, by heating it to a 
strong red heat in a crudble over a common 
fire^ till no blackness remains in the mass, 
stirring it frequentiy meanwhile with a me- 
tsllic wire. The loss of wdght will ascertain 
the quantity of animal and vegetable matter 
there wa% but not the proportions of cadi. If 



ANALYSI& 161 ANALYSIS. 

^ MoeQ wfngttcd, duriog this process^ resem^ much powdered charcoal, and kept at a red 

ble that of burnt feathers, it is a certain indi- heat in a cnidble for half an hour. The 

cation <^the presence of some animal matter ; mixture must then be boOed a quarter of an 

and a copious blue flame almost always de- hour in half a pint of water, and the solu^ 

notes a considerable proportion of vegetable tion, being filtered, exposed some days to the 

matter. Nitrate of ammonia, in the proper- open air. If any notable quantity of suU 

tion of twenty grains to a hundred of the re- phate of lime, or gypsum, existed in the soil, 

siduum of the soil, will greatly accelerate this a white precipitate will gradually form in the 

process, if the operator be in haste ; and not fluid, and the weight oi it will indicate the 

afiect the result, as it will be decomposed and proportion, 

evaporate. Phosphate of lime, if any be present, may 

8. What remains after this decomposition be separated from the soil after tlie process 
of the vegetable and animal matter, consists for gypsum. Muriatic add must be digested 
generally of minute particles of earthy mat- upon the soil in quantity more than suffident 
ter, which are usually a mixture of alumina to saturate the soluble earths. The solution 
and sUet with oxide of iron. To separate must be evaporated, and water poured upon 
these, boil them two or three houra in sul- the solid matter. Hiis fluid will dissolve the 
phuric acid diluted with four times its weight compounds of earths with the muriatic add» 
of water, allowing a hundred and twenty and leave the phosphate of lime untouched, 
grains of add for every hundred grains of 11. When the examination of a soil is 
the residuum. completed, the products should be clawed, 

If any thing I'emain undissolved by this and their quantities added together ; and if 
add, ft may be considered as silex, and be they nearly equal the original quantity of soil» 
separated, washed, dried, and wdghed in the the analysis may be considereid as accurate, 
usual manner. Carbonate of ammonia being It must however be observed, that when phofr. 
added to the solution, in quantity more than phate or sulphate of lime is discovered by the 
suffident to saturate the add, the alumina independent process. No. 10. just mentioned, 
will be predpitated ; and the oxide of iron, a correction must be made for the general 
if any, may be separated from the remaining process, by subtracting a sum equal to their 
liquid by boiling it. It scarcely ever hap- weight from the quantity of carbonate of lime 
pens that any magnesia or lime escapes solu- obtained by predpitation from the muriatic 
tion in the muriatic aqid ; but if it should, add. In arranging the products, the form 
it will be found in the sulphuric add ; from should be in the order of the experiments by 
which it may be separated as directed above which they are obtained. Thus 400 grains 
for the muriatic. This method of analysis is of a good siliceous sandy soil may be sup- 
suffidently predse for all common purposes ; posed to contain- 
but if very great accuracy be an object, the Grm 
residuum after the incineration must be treats Of water of absorption, - . 18 
ed with potash, and in the manner in which Of loose stones and gravel, prindpally 
stones are analyzed, as gjven in the first part siliceous, .... 42 
of this artide. Of undecompounded vegetable fibres, 10 

9. If the soil contained any salts, or soluble Of fine siliceous sand, - - 800 
vegetable or animal matter, they will be found Of minutely divided matter, separated 

in the water used for separating the sand. by filtration, and consisting of— 

This water must be evaporated to dryness at Carbonate of lime, - - 25 

a heat bdow boiling. If the solid matter Carbonate of magnesia, - 4 

left be of a brown colour, and inflammable, Matter destructible by heat, prin- . 

it may be considered as partly vegetable ex- cipally vegetable^ - - 10 

tract. If its smell, when expos^ to heat, Silex, . - - . 40 

be strong and fetid, it contains animal, mu- Alumina, • - - 32 

dlaginous, or gelatinous matter. If it be Oxide of iron, ... 4 

white and transparent, it may be considered Soluble matter, priticipally sul- 

as prindpally saline. Nitrate of potash or phate of potash and vegetable 

of lime is indicated in this saline matter by extract, ^ . . 5 

its sparkling when thrown on burning coals ; Gypsum, - - . - 3 

sulphate of magnesia may be detected by its Phosphate of lime, . . 2 

bitter taste > and sulphate of potash produces — 1^ 

DO alteration in a solution of carbonate of ~~~ 

ammonia, but predpitates a solution of mu- Amount of all the products, 395 

riate of baryta. Loss, - - - - 5 

10. If sulphate or phosphate of lime be — 
suspected in the soil, a particular process is 400 
requisite to detect it. A given weight of the 

entire soil, as four hundred grains for in- In this instance the loss is supposed small ; 

stance, must be mixed with one-third as but in general, in actual experiment^ it will 

L 



ANALYSIS. 163 ANALTSI& 

be found mudi greater, in consequence of tary bodies. MM. Gay Lussac and Thenaid 
the difficulty of collecting the whole quanti- contriTed a very elegant apparatus for Tege- 
ties of the different precipitates ; and when table and animal analysis, in which the mat- 
it is within thirty for four hundred grains, ter in a dried state was mixed with chlorate 
there is no reason to suspect any want of of potash, and formed into minute pellets, 
due precision in the processes. These pellets being projected through the in- 

12. When the experimenter is become ac- tervention of a stopcock of peculiar structure 
quainted with the use of the different instru- into an ignited glass tube, were instantly re- 
ments, the properties of the reagents, and solved into carbonic acid and water. The 
the relations between the external and chemi- former product was received over mercury, 
cal qualities of soils, he will seldom find it and estimated by its condensation with pot^ 
necessary to perform, in any one case, all the ash ; the latter was intercepted by ignited 
processes that have been described. When muriate of lime, and was measured by the 
his soil, for instance, contains no notable pro- increase of weight which it communicates to 
portion of calcareous matter, the action of this substance. By prerious trials, the quan- 
the muriatic acid. No. 6. may be omitted : tity of oxygen which a given weight of the 
in examining peat soils, he will principally chlorate of potash yielded by ignition was 
have to attend to the operation by fire and known ; and hence the carbon, hydrogen, 
air. No. 7. ; and in the analysis of chalks and and oxygen, derived from the organic sub- 
loams, he will often be able to omit the ex- stance, as well as the residual axote of the 
periment with sulphuric acid. No. 8. gaseous products. 

In the first trials that are made by persona M. Berzelius modified the above apparatus, 
unacquainted with chemistry, they must not and employed the organic product in combi- 
expect much precision of result Many dif- nation with a base, generally oxide of lead, 
ficulties will be met with ; but in overoom- He mixed a certain weight of this neutral 
ing them the most useful kind of practical compound with a known quantity of pure 
knowledge will be obtained ; and nothing is chlorate of potash, and triturated the whole 
so instructive in experimental science as the with a large quantity of muriate of soda, for 
detection of mistakes. The correct analyst the purpose of moderating the subsequent 
ought to be well grounded in general chemi- combustion. This mingled dry powder is 
cal information ; but perhaps there is no bet- put into a glass tube about half an inch dia- 
ter mode of gaining it than that of attempt- meter, and eight or ten inches long, wliich is 
ing original investigations. In pursuing his partially enclosed in a fold of tin-plate, hoop- 
experiments, he will be continually obh'ged ed with iron wire^ One end of the tube is 
to learn from books the history of the sub- hermetically sealed beforehand, the other is 
stances he is employing or acting upon ; and now drawn to a pretty fine point by the blow- 
his theoretical ideas will be more valuable in pipe. This termination is inserted into a 
being connected with practical operation, and glass globe about an inch diameter, which 
acquired for the purpose of discovery. joins it to a long tube containing dry muriate 

The analysis of vegetablet requires various of lime in its middle^ and dipping at its other 
manipulations and peculiar attention, as their extremity into the mercury of a pneumatic 
principles are extremely liable to be altered trough. The first tube, with its protecting 
by the processes to which they are subjected, tin case, being exposed gradually to ignitioiit 
It was long before this analysis was brought the enclosed materials are resolved into ear- 
to any degree of perfection. bonic acid, water, and axote, which come over. 

Some of the immediate materials of vege- and are estimated as above described. M. 
tables are separated to our hands by Nature Gay Lussac has more recently employed per- 
in a state of greater or less purity ; as the oxide of copper to mix with the organic sub- 
gums, resins, and balsams, that exude from stance to be analyzed ; because, while it yields 
plants. The expressed juices contain various its oxygen to hydrogen and carbon, it is not 
matters, that may be separated by the appro- acted on by azote ; and thus the erron re- 
priate reagents. Macoation, infusion, and suiting from the formation of nitric acid with 
decoction in water, take up certain parts so- the chlorate of potash are avoided. Berzelius 
luble in this menstruum ; and alcohol will has afiTorded satisfactory evidence by his an*, 
extract others that water will not dissolve, lyses, that the simple apparatus which he em- 
The mode of separating and extinguishing ployed is adequate to every purpose of che^ 
these materials will easily be collected from mical research. Dr Prout has described, in 
their characters, as given under the head V£- the Annals of Philosophy for March 1820, a 
GETABLB KINGDOM, and under the difierent very neat form of apparatus for completing 
articles- themselvesi analyses of organic substances with the heat 

As the ultimate constituents of all vegeta- of a lamp. Hydrogen having the power in 

ble substances are carbon, hydrogen, and oxy- minute quantities of modifying the constitu- 

gen, with occasionally azote, the problem of tion of the organic bodies, requires to be esti- 

their final analysis resolves into a method of mated with corresponding minuteness. M. 

ascertaining the proportion of these elemea- Porrett has very ingeniously suggested, that 



ANALYSIS. 163 ANALYSI& 

kB quantitjr may be more accurately deter- bon, while the latter states the carbon at only 

mined by the proportion of oxide of copper 40. 

that is rerived, than by the product of water. Tlie objects of the present paper are^ firrt. 

Dilute sulphuric acid being digested on the to indicate, and endeavour to remove several 

residua] cupreous powder, will instantly dis- sources of fallacy attending the method with 

solve the oxide, and leave the reduced metal ; peroxide of copper ; and next, to exhibit the 

wboae weight will indicate, by the scale of results of its application to a considerable 

equivalents, the hydrogen expended in its series of vegetable and animal compounds, 
leduction. One of hydrogen corresponds to Peroxide of copper, prepared by igniting 

nine of water, and to thirty-two of copper. the pure nitrate of this metal, is, like yellow 

From my experiments I iind, that this pro- oxide of lead, and many other metallic oxides, 

posal of M. Porrett will not suit in practice ; readily absorbent of a small portion of hu- 

for much of the peroxide of copper is occa- midity from the air, the quantity of which 

sionally reduced merely to the state of prot- depends, in some measure, on the length of 

oxide. time during whidi it has sufibred ignition. 

Under the different vegetable and animal If exposed to a red beat merely till the va- 

products, we shall take care to state their pours of nitric acid are expelled, 100 grains 

ultimate constituents by the most correct of the oxide will absorb, in the ordinary state 

and recent analysis. The peculiar substances of the atmosphere, from 1-lOth to ^lOtbs 

wbadi water, alcohol, ether, and other sol- of a grain of moisture in the space of an hour 

▼ents, can separate from an organic body, or two, and about one-half of the above 

may be called the immediate products of the quantity in a very few minutes. The French 

vegetable or animal kingdom ; while the car- chemists, who have operated most with this 

bon, hydrogen, oxygen, and azote, discover- agent, seem to be well aware of this circum- 

akAs by igneous analysis, are the ultimate con- stance, for they direct the peroxide to be used 

adtuent elements. To the former class be- immediately titer ignition, and to be tritu- 

kmg sugar, gum, starch, oils, resins, gelatin, rated with the organic matter in a hot mor- 

area, organic acids and alkalis, &c which tar of agate or glass. Yet this precaution will 

see. not entirely prevent the fallacy arising from 

The following account of my mode of exe- the hygrometric action ; for I find that per- 

cnting the ultimate analysis of organic pro- oxide thus treated does absorb, during the 

ducts, is extracted from a paper which the long trituration essential to the process, a 

Royal Sode^ did me the honour to insert in certain quantity of moisture, which, if not 

their Transactions for 1822. taken into account, will produce serious er- 

Hie improvements lately introduced into rors in the analytical results. It is better 
the analysis of vegetable and animal com- therefore to leave the powdered peroxide in* 
pounds, with the investigation of the equi- tended for research exposed for such time to 
▼alent ratios in which their constituent ele- the air as to bring it to hygrometric repose, 
ments, carbon, hydrogen, oxygen and azote, then to put it up in a phial, and by igniting 
are associated, luive thrown an unexpected one hundred grains of it in a proper glass 
light into this formerly obscure province of tube, sealed at one end, and loosely closed 
chemical science. While the substitution by with a glass plug at the other, to determine 
- M. Gay Lussac, of black oxide of copper for the proportion of moisture which it contains, 
the chlorate of potash, has given peculiar fa- This, then, indicates the constant quantity to 
olity and d^anoe to aninuU analysis, it may be deducted from the loss of weight which 
be doubted whether, in those cases where the the peroxide suffers in the course of the ex- 
main object of inquiry is the proportion of penment. The mortar should be perfectly 
carbon, it has not, frequently, led to fallad- dry, but not warm. 

ous results. As the quantity of this element Experimenters have been at great pains to 
Ss inferred from the volume of carbonic acid bring the various organic objects of research 
evolved in the decomposition of the organic to a state of thorough desiccation before mix- 
matters, such of their particles as happen not ing them with the peroxide of copper; but 
to be in immediate contact with the cupreous this practice introduces a similar fallacy to 
oxide^ will remain unconverted into csirfoonic that above described. We ought, therefore, 
add ; and thus the proportion of carbon will after having made them as dry as possible by 
come to be underrated; an accident which the joint agencies of heat and an absorbent 
caimot occur with chlorate of potash, since surface of sulphuric add m tfacuot to ezpoae 
the carbonaceous matter is here plunged in them to the air till they also come into hy- 
an ignited atmosphere of oxygen. It is pro- grometric repose, noting the quantity of mois- 
bab^ to this cause that we must refer the dis- ture which they imbibe, that it may be afker- 
crepant results, in the analysis of pure sugar, wards allowed for. The plan which I adopt 
between MM. Gay Lussac, Thenard, and for the purpose of desiccation seems to an- 
BerzeliuB, on the one hand, and Dr Front swer very welL Having put the pulverulent 
on the other ; the former gentlemen assign- animal or vegetable matter into short phials, 
ing about 43 parts in the hundred of car- furnished witfi ground glass stoppers, I place 



ANALYSI&. 164 ANALYiSIS. 

Ih'e open phiab in a iai^ quantity of sand* within the graduated receiver at e. ' By this' 

heated to 212^ F. in a porcelain capsule, and arrangement, should the collar be not ab80> 

set this over a surface of sulphuric acid in an lutely air-tight, the pressure of the column of 

exhausted receiver. After an hour or more mercury causes the atmospheric air to enter 

the recdver is removed, and the phials in- at the crevice, and bubbles of it will be seen 

fltantly stopped, llie loss of weight shows rising up without the application of heat At 

the total moisture which each of them has the end of the operation, the point of the tube 

parted with ; while the subsequent increase e is always left above the surface of the mer- 

of their weight, after leaving them unstopped cury, the quantity of organic matter em- 

fbr some time in the open air, indicates the ployed being such as to produce from six to 

amount of hygrometric absorption. This is seven cubic inches of gaseous product, the 

consequently the quantity to be deducted in volume of the graduated receiver being seven 

calculating experimental results. cubic inches. 

Many chemists, particularly in this coun- As the tubes with which I operate have all 
try, have employed the beat of a spirit-lamp, the same capacity, vis. half a cubic inch; and 
instead of that produced by the combustion as the bulk of materials is the same in all the 
of charcoal, for igniting the tube in which experiments, one experiment ob the analysis 
the mixed materials are placed. I have com- of sugar or resin gives the volume of atmo- 
pared very carefully both methods of heating, spheric air due to the apparatus ; which vo- 
and find that for many bodies, such as coal lume is a constant quantity in the same cir* 
and resin, which abound in carbon, the flame cumstances oif ignition. . And since the whole 
of the lamp is insufficient ; while its applica- apparatus is always allowed to cool to the 
tion being confined at once to a small portion atmospheric temperature, the volume of resi- 
of the tube, that uniform ignition of the dual gas in the tubes comes to be exactly 
whole, desirable towards the close of the ex- known, being equal, very nearly, to the pri- 
periment, cannot be obtained. I was hence mitive volume' of atmosph^c air left after 
led to contrive a peculiar form of furnace, in the absorption of the carbonic add in the su- 
which, with a handful of charcoal reduced gar or resin experiment* Tlius this quantity, 
to bits about the size of small filberts, an hitherto ill appreciated or n^lected in many 
experiment may be completed without anxie- experiments, though it is of very great conse- 
ty or trouble, in the space of half an hour, quence, may be accurately found. At 4r, fig. 
Since I have operated with this instrument, 2. a little tin-plate screen is shown. It is per- 
the results on the same body have been much forated for the passage of the tube,, and may 
more consbtent than those previously obtain- be slid along, and Idfl at any part of the se- 
ed with the lamp ; and it is so convenient, mi-cylindric cage, so as to preserve from the 
that I have sometimes finished eight experi- influence of the heat any requisite portion of 
ments in a day. the sealed end of the tube. At fig. 4i. is 

Fig. 1. (Plate VI.) represents the whole seen the shape of the little bulb, into which 

apparatus, as when in action. Fig. 2. is a I introduce the proper weight of ether, aloo- 

horizontal section of the furnace, in which we hoi, naphtha, or other volatile liquids which 

perceive a semi-cylinder of thin sheet-iron, are destined for analysis. After weighing it 

about eight inches long and 3^ wide, perfo- exactly, it b immediately slid down to the 

rated with holes, and resting on the edge of bottom of the tube, and covered with 150 or 

a hollow prism of tin-plate, represented more 200 grains of peroxide of copper. The bulb 

distinctly in fig. 3. where n shows a slit, has a capacity equal to 3 grain measures of 

through which the sealed end of the glass water, and its capillary point is sometimes 

tube may be made to. project, on occasion, closed with an inappreciably small quantity 

t is a handle attached to the semi^cylinder, by of bees-wax, to prevent the exhalation of the 

^hich it may be slid backwards or forwards, liquid till the peroxide be ignited, 

and removed at the end of the process. d\& 6 is a cover to the furnace^ with an oblong 

a sheath of platinum foil, which serves, by orifice at its top. It serves for a chimney, 

aid of a wire laid across, to support the mid- and may be applied or removed by means of 

die of the tube, when it is softened by igni- its handle, according as we wish to increase 

tion. At g, the plates which close the ends or diminish the heat cc are tin cases en* 

of the semi-cylinder and tin-plate prism, rise closing corks, through which the iron vrires 

up a few inches to screen the pneumatic ap- are piused, that support the whole furnace at 

paratus from the heat A third occasional any convenient height and angle of Inclina- 

screen of tin-plate is hung on at^I All these tion. 

are furnished with slits for the passage of the The tightness of the apparatus at the end 

^ass tube. This is made of crown glass, and of the process is proved by the rising of the 

is generally about nine or ten indhes long, 

and 3-lOths of internal diameter. It is con- 



nected with the mercurial cistern by a nar- • If be the capacity of the graduated reoeivcr, 
row tube and caoutchouc collar. This tube •"** * "** ■**" opacity of the tubes, then the above 
has a syphon form, and rises about an inch ▼ol«»« ^ * " J+i* 



ANALYSIS. 



165 



ANALYSI& 



mcrcufy in the graduated recover by aboiit 
one-tenth of an ioch, as the tube becomes 
lefrigerated. 

• Mj mode of operattng with the peroxide 
of copper is the following :•— 

I triturate very carefully in a dry glass 
mortar, from 1 to 2^ grains of the matter to 
be analyzed, with from 100 to 140 grains of 
the oxide. I then transfer it, by means of a 
platinum-foil tray and small glass funnel, 
into the glass tube, clearing out the mortar 
with a metallic brush. Over that mixture I 
put 20 or 30 grains of the peroxide itself, 
and next, 50 or 60 grains of clean copper 
filings. The remaining part of the tube is 
loosely closed with 10 or 12 grains of amian- 
thus, by whose capillary attraction the mois- 
ture evolTed in the experiment is rapidly 
withdrawn from the hot part of the tube, and 
the risk of its fracture thus completely obvi- 
atedl The amianthus serves moreover as a 
plug, to prevent the projection of any minute 
particles of filings, or of oxide, when the fil- 
ings are not present. The tube is now weigh- 
ed in a Tery delicate balance, and its weight 
is written down. A little cork, channelled 
«t its side, is next put into the tube, to pre* 
.▼ent the chance of mercury being fcMtred 



backwards into it^ by any accidental cooUog 
or condensatiooi. llie collar of caoutchouc 
is finally tied on, and the tube is placed* aa 
is shown in fig. 2. but without the plate kf 
which is employed merely in the case of ana^ 
lyzing volatile liquids. A few fragments of 
ignited charcoal are now placed Under the 
tube, at the end of the furnace next to the 
cistern, and the remaining space in the semi- 
cylinder is filled up with bits of cold charcoal. 
The top, b, may then be put in its place, 
when Uie operation will proceed spontaneous- 
ly, the progressive advance of the ignition 
from one end to the other being proportioned 
to the expansion of glass, so that the ti^ 
very seldom cracks in the process. Indeed 
I have often used the same tube for a doaen 
experiments, in the course of which it be- 
came converted into vUrite, cr Reaumur's 
porcelain. 

Since the evolved gas is saturated with 
moisture, I reduce it to the volume of dry 
gas, by help of the following table, computed 
by tile well known formula from my table of 
the elastic force of steam, which the Royal 
Society did me the honour to publish in their 
Transactions for the year 1818. 



Temper, 
ature. 


MuIdpUer. 


Temper, 
ature. 


HultlpUer. 


Temper, 
ature. 


MultipHer. 


53PF. 

54 

55 

56 

57 

58 

59 


0.9870 
0.9864 
0.9858 
0.9852 
0.9846 
0.9839 
0.9833 


60OF. 

61 

62 

63 

64 

65 

66 


0,9827 
9a 20 
9a 13 
98.06 
97.99 
97.93 
97.86 


67«>F. 

68 

69 

70 

71 

72 

73 


97.79 

97.72 

97.65 
0.9758 
0.9751 
0.9743 
0.9735 



In certain cases, where the quantity of hy- 
drogen is small, or where, as in the example 
of indigo, its presence has been denied, I em- 
ploy pulverulent protochloride of mercury 
(calomel) instead of peroxide of copper. The 
oi^nic compound being intimately mixed with 
that powder, and gentiy heated, the muriatic 
acid gas obtained demonstrates the presence, 
-tiiou^ half of its Tolume will not give the 
total quantity, of hydrogen ; for a proportion 
of this elementary body continues associated 
with oxygen in the state of water. Dry ox- 
alate of lead, treated in this way, yields not 
the slightest trace of muriatic acid ; for, on 
passing the disengaged gas through a dilute 
solution of nitrate of silver, no precipitation 
or even cloud of chloride is produced. But 
five grains of indigo, prepared from the de- 
oxidized solution of the dyer's vat, and freed 
from its lime and resin by the successive ap- 
plication of dilute muriatic acid and alcohol, 
gave five cubic inches of muriatic acid gas 
when heated along with 150 grains of calo- 
mel. Here we have a quantity of gas equi- 



yalent to 2^ cubic inches of hydrogen. By 
meansof peroxide of copper, however, nearly 
4 times the above quantity of hydrogen may 
be obtained from the same weight of indigo. 

I shall now give in detail one example of 
the mode of computing the relation of the 
constituents from the experimental results, 
and shall then state the other analyses in a 
tabular form, subjoining a few remarks on 
the habitudes of some peculiar bodies. 

1.4 grains of sulphuric ether, specific gra- 
vity 0.70, bdng slowly passed in vapour from 
the glass bulb through 200 grains of ignited 
peroxide of copper, yielded 6.8 cubic inches 
of carbonic add gas at 66^ F. which 'are 
equivalent to 6.57128 of dry gas at 60^. 
This number being multiplied by 0. 127 =: 
the carbon in one cubic inch of the gas, the 
product 0.8345256, is the carbon in 1.4 
grains of etiier; and 0.8345256 X 7 ^ 
2.2254 =s tLe oxygen equivalent to the car- 
bonic acid. The tube was found to have 
lost 4.78 grains in weight, 0. 1 of which was 
due to the hygrometic moisture in the oxide, 



ANATAS£. 



166 



ANHYDRITE. 



and 1.4 to the ether. The remainder^ &S8» 
is the quantity of oxygen abstracted from the 
oiide by the combustible elements of the 
ether. But of these 3.28 grains, 2.2254* 
went to the formation of the carbonic add, 
leafing 1.0546 of oxygen, equivalent to 
0.1318 of hydrogen. Hence, 1.4 ether, by 
this experiment, which is taken as the most 
satisfiurtory of a great number, seem to con- 
sist of 

Carbon, 0.8345 

Hydrogen, 0.1318 

Water, 0.4337 



1.4000 
And in 1 grain we shall hafe,— • 
Caxbon, 0.5960 3 atoms 2.25 
Hydrogen, 0.1330 4 atoms 0.50 
Oxygen, 0.2710 1 atom 1.00 

1.0000 a75 

Or, 3 vols olef. gasssr 3 X 0.9722=r 
2 Tap. of water, 2x 0.625 s 



60.00 
ia33 
26.66 

■■■■.^■Ml 

100.0 

2.9166 

1.25 



4.1666 
llie proportion of the constituentB of sul- 
phuric ether, deduced by M. Gay Lussac 
from the experiments of M. Tb. de Saussure, 
are 2 volumes olefiant gas -^ 1 volume va- 
pour of water, which' 3 volumes are condensed 
into 1 of vapour of ether, having a specific 
gravity s= 2.58. The ether which I used 
had been first distilled off dry carbonate of 
potash, and then digested on dry muriate of 
lime, from which it was simply decanted, ac- 
cording to the injunction of M. de Saussure. 
Whether my ether contained more alcoholic 
matter than that employed by the Genevese 
philosopher, or whether the difference of re- 
sult is to be ascribed to the difference in the 
mode of analysis, must be decided by future 



By analogous modes of reduction, the re- 
sultb were deduced from my experiments. I 
ought here to state^ that in many cases the 
materials, after being ignited in the tube, and 
then cooled, were again triturated in the mor- 
tar, and subjected to a second ignition. Thus, 
none of the carbon could escape conversion 
into carl>onic add. I was seldom content 
vrith one experiment on a body : frequently 
six or eight were made. 

AN ATASE. Octohedrite, oxide of tita- 
nium, rutile, and titane rutile. This mineral 
shows a variety of colours by reflected light, 
frte indigo-blue to reddish-brown. By 
transmitted light it appears greenish-yellow. 
It is found usually in small crystals, octohe- 
drons, with isosceles triangular faces. Struc- 
ture lamellar ; it is semitransparent or opaque ; 
fragments splendent, adamantine; scratches 
glass ; brittle ; sp. gr. 3.85. It ift a pure oxide 
of titanium. It has been found only in Dau- 
phiny and Norway ; and is a very rare mine- 



raL It occurs in granite, gneiss, mica slater 
and transition lime-stone. 

ANDALUSITE. A massive mineral, 
of a flesh, and sometimes rose-red colour. 
It is, however, occasionally crystallised in 
rectangular four-sided prisms, verging on 
rhomboids. The structure of the prisms ia 
lamellar, with joints parallel to their sides. 
Translucent; scratches quartz; is easily 
broken; sp. gr. 3.165. Infusible by the 
blowpipe; in which respect it differs from 
felspar, though called felspath apyre by Haiiy. 
It is comppwd of 52 alumina, 32 silica, 8 
potash, 2 oxide of iron, and 6 loss.— Foti^. 
It belongs to primitive countries, and waa 
first found in Andalusia in Spain. It is found 
in mica slate in Aberdeenshire, and in the 
Isle of Unst ; Dartmoor in Devonshire ; in 
mica slate at Killiney, near Dublin, and at 
Douce Mountain, county Wicklow. 
ANDREOLITE. See Haamotom^ 
ANHYDRITE. Anhydrous gypsum. 
There are six varieties of it :*— 

1. Compact; has various shades of white, 
blue, and red; massive and kidney^shaped; 
dull aspect ; splintery or conduudal fracture ; 
translucent on the edges; is scratched by 
fluor, but scratches ode spar; somewhat 
tough ; spedfic gravity 2.850. It is dry sul- 
phate of lime, with a trace of sea salt It is 
found in the salt mines of Austria and Salz- 
burg, and at the foot of the Harz mountains. 
2. Granular ; the scaly of Jameson, is found 
in massive concretions, of which the structure 
is confusedly foUated. White or bluish 
colour, of a pearly lustre; composition as 
above, with one per cent of sea salt It oc- 
curs in the salt mines of Halle ; sp. gr. 2.957. 
3b Fibrous; massive, glunmering, pearly 
lustre; fracture in delicate paralld fibres; 
scarcely translucent ; easily broken. Found 
at Halle, , Ischel, and near Brunswick. 
4. Radiated. Blue sometimes spotted with 
red; radiated, splendent fracture; partly 
splintery ; translucent ; not hard ; sp. gr. 
2.940. 5. Sparry, or cube spar. Milk- 
white colour, passing sometimes into greyish 
and reddish-white; short four-sided prisms, 
having two of the opposite sides much broader 
than Sie other two ; and occasionally the la- 
teral edges are truncated, whence results an 
eight-sided prism ; lustre splendent, pearly ; 
foliated fracture ; threefold rectangular deav- 
age; cubical fragments; translucent; scratch- 
es oalc spar; brittle; sp. gr. 2.9. This is 
the muriadte of some writers. It is doubly 
refracting. It is said to contain one per cent 
of sea salt It is found at Bex in Switzer- 
land, and Halle in the Tyrol. 6. Silidfe- 
rous, or vulpinite. Massive concretions of 
a laminated structure; translucent on the 
edges; splendent and brittle; greyish-white, 
vdned with bluish-grey ; sp. gr. 2.88. It 
contains eight per cent silex ; the rest is sul- 
phate of lime. It is called by statuaries^ 



ANIMAL KINGDOM. 167 ANNEAL. 

Msnno bardiglio di Bergamo, and takes a The foUowiog are the peculiar chemical 

fine polish. It derives its name from Vul- products of animal organization {—Gelatin, 

pino in Italy, where it accompanies lime. albumen, fibrin, fat, caseous matter, colouring 

ANHYDROUS. Destitute of water. matter of blood, mucus, urea, picromel, osma- 

ANIL, or NIL. Hiis plant, from the some, sugar of milk, and sugar of diabetes. 

leaves of which indigo is preparefi^ grows in (See also the b'st of Acids Organic, for seve- 

America. ral animal products.) The compound animal 

ANIMAL KINGDOM. Animal bodies products are the various solids and fluids, 

may be considered as peculiar apparatus for whether healthy or morbid, that are found in 

carrying on a determinate series of chemical the animal body; such as muscle, skin, bone, 

operations. Vegetables seem capable of ope- blood, urine, bile, morbid concretions, brain, 

rating with fluids only, and at the temperature &c. 

of the atmosphere. But most animals have When animal substances are left ^posed 

a provision for mechanically dividing solids to the air, or immersed in water or other 

by mastication, which answers the same pur- fluids, they suffer a spontaneous change, 

pose as grinding, pounding, or levigation does which is more or less rapid according to cir- 

in our experiments ; that is to say, it enlarges cumstances. The spontaneous change of or- 

the quantity of surijace to be acted upon by ganized bodies is distinguished by the name 

solvents. The process carried on in the of fermentation. In vegetable bodies there 

stomach appears to be of the same kind as are distinct stages or periods of this process, 

that which we distinguish by the name of di- which have been divided into the vinous, 

gestion ; and the bowels, whatever other uses acetous, and putrefactive fermentations. Ani- 

tbey may serve^ evidently form an apparatus mal substances are susceptible only of the two 

for filtering or conveying off the fluids ; latter, during which, as in all other sponta- 

while the more solid parts of the aliments, * neous changes, the combinations of chemical 

which are probably of such a nature as not principles become in general more and move 

to be rendered fluid, but by an alteration ' simple. There is no doubt but much instruc- 

which would perhaps destroy the texture of tion might be obtained *from accurate obser- 

the machine itself, are rejected as useless, vations of the putrefactive processes in all 

When this filtered fluid passes into the drcu- their several varieties and situations ; but the 

latory vessels, through which it is driven with loathsomeness and danger attending on such 

considerable velocity by the mechanical action inquiries have hitherto greatly retarded our 

of the heart, it is subjected not only to all progress in this department of chemical 

those changes which the chemical action of science. See Feamentation (Potrefac- 

its parts is capable of producing, but is like- tive). 

wise exposed to the air of tlie atmosphere in ANIME, improperly called gum-anime, 
the lungs, into which tliat elastic fluid is ad- is a resinous substance imported from New 
mitted by the act of respiration. Here it Spain and tHe Brazils. ' There are two kinds, 
undergoes a change of the same nature as d^tinguished by the names of oriental and 
happens to other combustible bodies, when occidental. Tlie former is dry, and of an un- 
Chey combine with its vital part, or oxygen, certain colour, some specimens being green- 
This vital part becomes condensed, and com- ish, some reddish, and some of the brown 
bines with the blood, at the same time that it colour of myrrh. Tlie latter is in yellow- 
gives out a large quantity of heat, in conse- ish-white, transparent, somewhat unctuous 
quence of its own capacity for heat being di- tears, and partly in larger masses ; brittle, of 
minislied. A small portion of azote likewise a light pleasant taste, easily melting in the 
is absorbed, and carbonic acid is given out fire, and burning with an agreeable smell. 
Some curious experiments of SpaUanzani Like resins, it is totally soluble in alcohod, 
show, that the lungs are not the sole organs and also in oil. Water takes up about I- 16th 
by which these changes are effected. Worms, of the weight of this resin by decoction. The 
insects, shells of land and sea animals, egg spirit, drawn off by distillation, has a con- 
shells, fishes, dead animals, and parta of ani- siderable degree of the taste and flavour of 
mals, even after they have become putrid, are the anime ; the distilled water discovers on 
capable of absorbing oxygen from the air, and its surface some small portion of essential oil. 
giving out carix)nic add. Tliey deprive at- This resin is used by perfumers, and also 
naojpberic air of its oxygen as completely as in certain plasters, wherein it has been sup- 
phosphorus. Shells, however, lose this pro- posed to be of service in nervous affections of 
perty when their organization is destroyed by the head and other parts; but there are no 
Mge. Amphibia, deprived of their lungs, reasons to think, that, for medical purposes, 
lived much longer in the open air, than otliers it differs from common resins. 
in air destitute of oxygen. It is remarkable, ANNEAL. We know too little of the 
that a larva, weighing a few grains, would arrangement of particles, to determine what 
consume almost as much oxygen in a given it is that constitutes or produces brittleness 
time, as one of the amphibia a thousand times in any substance. In a considerable number 
its bulk. of instances of bodies which are capable of 



ANORTHITE. 168 ANTIMOKY. 

undfirgoing ignitioii, it u found that ludden gles, distinguishes it from feUpur, two of 

cooling renders them hard and brittle. This whose cleavages are at right angles to each 

is a real inconvenience in glass, and also in other. 

steel, when this metallic substance is required ANTHOPHYLLITE. A massiTe mi- 
to be soft and flexible. Tlie inconveniencies neral of a brownish colour; sometimes also 
are avoided by cooling them very gradually ; crystallized in thin flat six-sided prisms, 
and thu process is called annealing. Glass streaked lengthways. It has a false metallic 
vessels, or other articles, are carried into an lustre, glistening and' pearly. In crystals, 
oven or apartment near the great furnace, transparent Massive ; only translucent on 
called the leer, where they are permitted to the edges. It does not scratch glass, but 
cool, in a greater or less time, according to fluate of lime. Specific gravity 3,^ Some* 
their thickness and bulk. The annealing of what hard, but exceedingly brittle. Infusible 
steel, or other metallic bodies, consists simply alone before the blowpipe, but with borax it 
in headng them, and suffering them to cool gives a grass-green transparent bead. It con- 
again, either upon the hearth of the furnace, sists of 56 silica, 13.3 alumina, 14 magnesia, 
or in any other situation where the heat is 3.33 lime, 6 oxide of iron, 3 oxide of man- 
moderate^ or at least the temperature is not ganese, 1.43 water, and 2.94 loss, in 100. It 
very cold. is found at Konigsbeig in Norway. 

ANNOTTO. The pelUcles of the seeds ANTHRACITE. Blind coal, Kilkenny 

of the bixa orellanth a liliaceous shrub, from coal, or glance coaL Hiere are three varieties. 

15 to 20 feet high in good ground, afford the 1. Massive, the concfaoidal of Jameson. Its 

red masses brought into Europe under the colour is iron-black, sometimes tamislied on 

name of Annotto, Orlean, and Roucou. the surface, with a splendent metallic lustr& 

The annotto commonly met with among us Fracture conchoidal, with a pseudo-metallic 

is moderately hard, of a brown colour on the ' lustre. It is brittle and light It yields no 

outside, and a dull red within. It is diffi- flame, and leaves whitish ashes. It is found 

culily acted upon b^ water, and tinges the in the newest floetz formations, at Meissncr 

liquor only of a pale brownish-yellow colour, in Hesse^ and Walsall in Staffbrdshire. 2. 

In rectified spirit of wine it very readily dis- Slaty anthracite. Colour black, or brownish- 

solves, and communicates a high orange or black. Imperfect slaty in one direction, with 

yellowish-red. Hence it is used as an ingre- a slight metallic lustre. Brittle. Specific 

dient in varnishes, for giving more or less of gravity 1.4 to 1.8. Consumes without flames 

an orange cast to the simple yellows. It is composed of 72 carbon, 13 silica, 3.3 

Sulphuric ether is the best solvent of an^ alumina, and 3.5 oxide of iron. It is found 

notto. Potash and soda, either caustic or in both primitive and secondary rocks : at 

carbonated, dissolve annotto in great quanti- Calton lUll, Edinburgh ; near Walsall, Staf- 

ties ; from which solutions it is ^rown down fordshire ; in the southern parts of Breck- 

by acids in small flocks. The alkaline solu- nockshire^ Carmarthenshire^ and Pembroke- 

tions are of a deep red colour. Chlorine de- shire, whence it is called Welsh culm ; near 

colours the alcoholic solution of annotto ; the Cumnock and Kilmarnock, Ayrshire ; and 

liquor becoming speedily white and milky, most abundantly at Kilkenny, Ireland. 3. 

If strong sulphuric acid be poured on annotto Columnar anthracite. In small short pris- 

in powder, the red colour passes immediately matic concretions, of an iron-black colour, 

to a very fine indigo blue : but this tint is not with a tarnished metallic lustre. It is brittle^ 

permanent ; it changes to green, and finally soft, and light It yields no flame or smoke, 

to violet, in the course of 24 hours thereafter. It forms a thick bed near Sanquhar in Dum- 

This property of becoming blue belongs also fries-shire ; at Saltcoats and New Cumnock 

to saffron. Nitric acid, slightly heated on in Ayrshire. It occurs also at Meissner in 

annotto, sets it on fire ; and a finely divided Hesse. 

charcoal remains. Annotto is soluble both ANTIMONY. The word antimony is 

in essential oils as oil of turpentine, and in used in commerce to denote a metallic orc^ 

fixed oils.—- '^oMMtngau^, Ann, de Chim, et consisting of sulphur combined with the metal 

de Phyt. xxviii. 440. which is properly called Antimony. Some^ 

Beside its use in dyeing, it is employed for times this sulphuret is termed crude anti- 
colouring cheese. mony, to distinguish it from the pure metal^ 

ANORTHITE. The primitive form of or regulus, as it was formerly called, 
this mineral is a doubly oblique prism. Hie Antimony is of a dusky-white colour, very 
lustre of the cleavages is pearly, and that of brittle, and of a plated or scaly texture. Its 
the conchoidal fracture vitreous. The crystals specific gravity, according to M. Brisson, is 
of anorthite are clear and transparent, but 6.7021, but Bergman m2ces it 6.86. Soon 
small. Sp. grav. 2.763. Strong muriatic add after ignition, about 800^ F., it melts, and by 
entirely decomposes it It consists of silica a continuance of the heat it becomes oxidised, 
44^49, alumina 34.46, oxide of iron 0.74, and rises in white fumes ; which may after- 
lime 15.68» magnesia 5.26.— Am^. The ward be volatilized a second time, or fused 
name anorthite, signifying without right an- into a hyacinthine glass, according to the 



Antimony. 169 antimony. 

siasBgement of the heat The lint were for- riadc acid, disengaging only sulphuretted 

naerly called argentine flowers of regulus of hydrogen. It is also formed by passing 

antimony. In closed vessels the antimony sulphuretted hydrogen through solution of 

rises totally without decomposition. This emetic tartar, or through butter of antimony 

metallic substance is not subject to rust by dissolved in water and tartaric add. It is in 

exposure to air, though its surface becomes this case of an orange colour, but is a simple 

tarnished by that means. sulphuret, as is also, according to him, kermes 

There are certainly three, possibly four dis- mineraL The latter substance yielded him, 

tinct oombinationa of antimony and oxygen, in 100 parts, 72,32 antimony -|- 27.68 sul- 

]. Tlie protoxide of- Berzelius is a blackish- phur. Now the native sulphuret by Bene- 

grey powder, obtained from a mixture of pow- lius contains 72.86 -|- 27.14; a near ap- 

der of antimony and water at the positive pole proximation. This seems to consist of U 

of a voltaic circuit. Heat enables this oxide metal -|- 4 sulphur, or to be a bisulphuret. 

to absorb oxygen rapidly, converting it into the The next sulphuret has an orange colour, 

tritoxide; According to Berzelius, it consists which resembles a good deal the golden sul- 

of 100 of metal, and 4.65 oxygen. It must phuret It is form^ by passing sulphuretted 

be confessed, however, that die data for fix- hydrogen through a solution of antimonious 

ing these proportions are very doubtful. 2. acid. Hie best way of procuring antimo- 

The deutoxide may be obtained by digesting nious add in solution, is to dissolve antimony 

the inetal in powder in muriatic add, and in aqua regia, and to evaporate the solution 

pouring the solution into water of potash, to dryness. Hie antimonic acid tlius formed 

Wash and dry the predpitate. It is a pow- b then ignited, to convert it into antimonious 

der of a dirty-white colour, which melts at acid ; which is to be melted with caustic 

a moderate red heat, and crystallizes as it potash, and the fused mass is to be treated 

cools. According to Berzehus, it consists of with hydrochloric add and water, till a dear 

84.3 metal -|- I5w7 oxygen. 3. Hie trit- liquor be obtained. Tlie sulphuret formed 

oxide^ or andmonions add, is the immediate as above from this solution consists of 66.35 

product of the combustion of the metal, metal -|- 33.65 sulphur. The third sulphu- 

called of old, from its fine white colour, the ret is the sufphur antimonU auratum, of 

argentine flowers of antimony. It may also which no analysis is given.— -^nn. de Chim> 

t>e formed by digesting hot nitric add on 1825. 

antimony. When fused with one>fourth of Chlorine gas and antimony combine with 
andmony, the whole becomes deutoxide. It combusdon, and a bichloride results. Hiis 
forms the salts called andmonites with the was formerly prepared by distilling a mixture 
different bases. According to Berzelius, the of two parts of corrosive sublimate with one 
tritoxide consists of about 80 metal -f> 20 of andmony. The substance which caAe 
oxygen. 4b The peroxide, or andmonic add, over, having a fatty consistence, -was called 
is formed when the metal in powder is ignited butter of andmony. It is frequendy cry». 
along with six times its weight of nitre in a tallized in four-sided prisms. It is fusible 
silver crudble. The excess of potash and and volatile at a moderate heat ; and is re- 
nitre being afterwards separated by hot water, solved by water alone into the white oxide 
the andmoniate of potash is then to be de- and muriadc acid. Bdng a bichloride, it is 
composed by muriadc add, when the insolu- emlnendy corrosive, like the bichloride of 
ble andmonic add of a straw Colour will be mercury, from wbidi it is formed. It con- 
obtained. Nitro-muriadc add likewise con- ststs of 45.7 chlorine 4~ ^3 andmony, 
verts the metal into the peroxide. Though according to Dr John Davy's analysis, when 
insoluble in water, it reddens the vegetable the composidon of die sulphuret is corrected 
blues. It does not combine with adds. At by its recent exact analysis by Berzelius. 
a red beat oxygen is disengaged, and anti- But 1 1 andmony -}- 2 primes chlorine ^ 
monioufl add results. Berzelius infers its 9.0, give the propordon per cent of 44. 1 .4. 
compoddon to be 76.34 metal -|- 23.66 55.5; a good coinddence, if we consider the 
oxygen. It is diflicult to reconcile die above circuitous process, by which Dr Davy's an*, 
three pordons of oxygen to one prime equi- lysis was performed. Three parts of com>- 
valent for andmony. The number 1 1 gives sive sublimate, and one of metallic andmony, 
the best approximadon to Berzelius's analy- are the equivalent propordons for making 
ses. We diall then have the , butter of andmony. 

7n 100 jxirts. Iodine and andmony combine by the aid 

Deutozidellmetal-}-2oxy. or 84.6-1- 15.4 of heat into a solid iodide^ of a dark red 

Tritoxide 11 +^ 7a6-f 21.4 colour. 

Peroxide 11 +^ 7a44- 26.6 The phosphuret of this metal is obtained 

The first oxide is too imperfecdy known by fusing it with solid phosphoric add. It 

to enter into the argument. is a white semi-crystalline substance. 

M. Rose of Berlin has ascertained the The sulphuret of andmony exists abun- 

existence of three sulphurets of andmony. dandy in nature. (See Ores of Antimony.) 

The nadvc mineral dissolves entirely in mu- It consists) according to Berzelius, of 100 



ANTIMONY. 



170 



ANTIMONY. 



aadmony -}- 87.25 suipbur. The propor- 
tion given by the above equivalent ratio is 
100 -|- 36.5. Other analysts have found 
30, 33, and 35, to 100 of metaL BerseUus 
admits that there may be a slight error in 
bis numbers. 

The only important alloys of antimony are 
those of lead and tin : the former constitutes 
type metal, and contains about one-sixteenth 
of antimony ; the latter alloy is employed for 
making the plates on which music is engraved. 
When this alloy is acted on by nitric acid 
with heat, the tin, in becoming an insoluble 
oxide, carries down with it the antimony, ac- 
cording to M. Bussolin. 

The salts of antimony are of two differ- 
ent orders : in the first, the deutoxide acts 
the part of a salifiable base; in the second, 
the tritoxide and peroxide act the part of 
acids, neutralizing the alkaline and other 
bases, to constitute the antimonites and anti- 
mff p ifttp ff t 

Tlie only distinct combination of the first 
order entitled to our attention, is the triple 
salt called tartrate of potash and antimony, 
or tartar emetic, and which, by M. Gay Lus- 
8ac*s new views, would be styled cream-tar- 
trate of antimony. This constitutes a valu^ 
able and powerful medicine, and therefore 
the mode of preparing it should be conectly 
and clearly defined. As the dull white 
deutoxide of antimony is the true basis of 
this compound salt, and as that oxide readily 
passes by mismanagement into the tritoxide 
or antimonious acid, which is altogether un- 
fit for the purpose, adequate pains should be 
taken to guard against so capital an error. 
In former editions of the British Pbarmaco- 
poeiaa, the glass of antimony was prescribed 
as the basis of tartar emetic. More complex 
and precarious formulae have been since in- 
troduced. The new edition of the Fharma- 
oop^ Fran9aise has given a recipe, which 
^>pears, with a sliglit change of proportions^ 
to be unexceptionable:— Take of the sulphu- 
retted vitreous oxide of antimony, levigated 
and acidulous tartrate of potash, equal parts. 
Form a powder, which is to be put into an 
earthen or nlver vessel, witli a suflSdent 
quantity of pure water. Boil the mixture 
for half an hour, adding boiling water from 
time to time ; filter the hot liquor, and eva- 
porate to dryness in a porcelain capsule; 
dissolve in boiling water the result of the 
evaporation; evaporate till the solution ac- 
quires the sp. grav. 1.161, and then let it 
repose, that crystals be obtained, which, by 
this process, will be pure. By another re- 
cipe, copied, with some alteration, from Mr 
I%ilips's prescription, into the appendix of 
the French Pharroacopceia, a subsulpbate of 
antimony is formed first of all, by digesting 
two parts of sulphuret of antimony at a mo- 
derate beat, with three parts of oil of vitriol. 
This insoluble subsulpbate being well washed, 



is then digested in a quantity of boiling water 
with its own weight of cream of tartar, and 
evaporated to the density of 1.161, after 
which it is filtered hot. On cooling, crystals 
of the triple tartrate are obtained. One might 
imagine, that there is a chance of obtaining by 
this process a mixture of sulphate of potash, 
and perhaps of a triple sulphate of antimony, 
along with the tartar emetic Probably this 
does not happen ; for it is said to yield crys- 
tals, very pure, very white, and without any 
mixture vrhatever. 

Pure tartar emetic is in colourless and 
transparent tetrahedrons or octohedrons. It 
reddens litmus. Its taste b nauseous and 
caustic Exposed to the air, it effloresces 
slowly. Boiling water dissoWes half its 
weight, and cold water a fifteenth part 
Sulphuric, nitric, and muriatic adds, when 
poured into a solution of this salt, predpitate 
its cream of tartar ; and soda, potash, ammo- 
nia, or their carbonates, throw down its oxide 
of antimony. Baryta, strontia, and lime wa- 
ters, occasion not only a predpitate of oxide 
of antimonj, like the alkalis, but also in- 
soluble tartrates of these earths. That pro- 
duced by the alkaline hydrosulphurets is 
wholly fimned of kermes ; while that caused 
by sulphuretted hydrogen contains both ker- 
mes and cream of tartar. The decoctions 
of several varieties of dnchona, and of seve- 
ral bitter and astringent plants, equally d&. 
compose tartar emetic; and the precipitate 
then always consists of the oxide of anti- 
mony, combined with the vq^table matter 
and cream of tartar. Fhysidans ought there- 
fore to beware of such incompatible mixtures. 
When tartar emetic is exposed to a red heat, 
it first blackens, like all organic compounds, 
and afterwards leaves a residuum of metallic 
antimony and subcarbonate of potash. From 
this phenomenon, and the deep brownish-red 
predpitate by hydrosulphurets, this antimo- 
nial combination may readily be recognized. 
The predpitate may further be dried on a 
filter, and ignited with black flux, when a 
globule of metallic antimony wiU be ob- 
tained. Infusion of galls is an active pre- 
cipitaqt of tartar emetic 

This salt, in an undue dose, is capable of 
acting as a poison. The best antidotes are 
demulcent drinks, infusions of bark, tea, and 
sulphuretted hydrogen water, which instantly 
converts the energetic salt into a relatively 
mild sulphuret: anodynes are useful after- 
wards. 'Hie powder of tartar emetic, mixed 
with bog's lard, and applied to the skin of the 
human body, raises small vesications. 

The composition of this salt, according to 
M. Thenard, b 35.4 add, 39.6 oxide, 16.7 
potash, and 8.2 water. The presence of the 
latter ingredient b obvious, . iVom the undis- 
puted phenomenon of efilorescence. By a 
recent analysis of Mr I'hilips, this salt is 
composed of-* 



ANTIMONY. ITl ANTIMONY. 

1 siombkwtrateofpotasb» 29.5 40.56 rat of potash or soda. The alkatfne has* 

3 atoms protoxide of antunoDy, 1 9.5 4S. 97 being laid hold of, the sulphuretted hydrogen 

3 atoms «rater, 3.375 7.45 and sulphur to which they were united, are 

— ^^ set at liberty ; the sulphur and kenqes fidl to- 

100.00 gether, combine with it, and form an orange- 

Dr Hiomson, however, assigns only 2 coloured compound, called the golden suU 

atoms of water, from his researches published phuret of antimony. It is a hydroguretted 

in hb work on the first principles of Chemis- sulphuret of antimony. Hence, when it is 

try. ILeir atomic number for the oxide of digested with warm muriatic add, a large 

antimony is one>half of mine. residuum of sulphur is obtained, amounting 

The deutoxide seems to have the property sometimes to 12 per cent. Kennes is com- 

of combining with sulphur in various pro- posed, by Thenanl, «f 20.3 sulphuretted hy- 

povtions. To this species of compound must drogen, 4.15 sulphur, 72.76 oxide of anti- 

be referred the liver of antimony, glass of noony, 2.79 water and loss ; and the golden 

antimony, and crocus melaliorum of the an- sulphuret consists of 17.87 sulphuretted 

ctent apothecaries. According to M. Sou^ hydrogen, 68.3 oxide of antimony, and 12 

beirsn, glass (tf antimony contains— protoxide sulphur. M. Rose apparently proves, that 

(deutoxide of Ben.) 91.5, silica 4.5, per- kennes is the same as the native sulphuret 

cxxide of iron 3.2, sulphuret of antimony of antimony. See above. 

1.9. Sulphuretted hydrogen forms, with the By evaporating the supernatant kennes 

deutoxide of antimony, a compound which liquid, and cooling, crystals form, which have 

possessed at one time great celebrity in medi- been btely employed by the calico printer to 

cine, and of vHiich a modification has lately give a topical orange. These crystals are dia- 

bcen introduced into the art of calico-printing, solved in water, and the solution being thick- 

By dropping hydrosulphnret of potash, or of ened with paste or gum, is applied to doth 

ammonia, into the cream tartrate, or into mild in the usual way. - After the cloth is dried, 

muriate d antimony, the hydrosulphuret of it is passed through a dilute add, when the 

die metallic oxide predpitates of a beautiful orange predpitate is deposited and fixed on 

deep orange odour. Hiis is kertnes mmeraL the vegetable fibres. 

Clusd's process for obtaining a fine kermest An empirical antimonial medicine, called 

fight, velvety, and of a deep purple-brown, is James's powder, has been much used in thu 

the following :— 'One part of pulverised suU country. Tlie inventor called it his fiver 

phuret of antimony, 22( parts of crystallized powder, and was so successful in his practice 

snbcaibonate of soda, and 200 parts of wa- with it, that it obtained very great reputation> 

ter, are to be boQed together in an iron pot. which it still in some measure retains. Pto>- 

Filter the hot liquor into warm earthen pans, bably the success of Dr James was in great 

and allow them to cool very slowly. At the measure owing to his free use of the bark» 

end of 24 hours the kennes is deposited, which he always gave as largely as the sto- 

Throw it on a filter, wash it with water which mach would bear, as soon as he had com- 

had been boiled and then cooled out of con« pletdy evacuated the primae viie by the use 

tact vrith air. Dry the kennes at a tempera- of his antimonial preparation, with which at 

ture of 85^, aqd preserve in corked phials.' first he used to combine some mercurial. His 

Whatever may be the process employed, by specification, lodged in Chancery, is as foU 

boiling the liquor, after cooling and filtration, lows :— " Take antimony, calcine it vrith a 

on new sulphuret of antiipony, or upon that continued protracted heat, in a flat, unglazed, 

which was left in the former operation, this earthen vessel, adding to it from time to time 

new liquid will deposit, on cooling, a new a suffident quantity of any animal oil and 

quantity of kermes. Besides the hydrosul- salt, well dephlegmated ; then boil it in 

phnretted oxide of antimony, there is formed melted nitre, for a considerable time, and 

a sulphuretted hydrosulphuret of potash or separate the powder from the nitre by dis- 

soda. Consequently, the alkali seizes a por- solving it in water." The real recipe has 

tion of the sulphttf from the antimonial sul- been studiously concealed, and a false one 

phuret, water is decomposed, and whilst a published in its stead. Different formulie 

portion of its hydrogen unites to the alkaline have been offered for imitating it. That of 

sulphuret, its oxygen, and the other portion Dr Pearson furnishes a mere mixture of an 

of its hydrogen, combine with the sulphuret- oxide of antimony with phosphate of lime. 

ted antimony. It seems, that the resulting The~real powder of James, according to this 

kermes remains dissolved in the sulphuretted chemist, consists of 57 oxide of antimony, 

hydrosulphuret c^ potash or soda ; but as it vrith 43 phosphate of lime. It seems highly 

is less soluble in the cold than the hot, it is probablethat superphosphate of lime would act 

partially precipitated by refrigeration. If on oxide ofantimony in a way somewhat simi- 

we pour into the supernatant liquid, after the lar to cream of tartar, and produce a more che- 

kermes is deposited and removed, any add, mical combination than wliat can be derived 

as the dilute nitric, suljrfiuric, or muriatic, from a precarious ustulation, and calcination, 

we deoompoie the sulphuretted hydiosulphu- of hartshorn ihavings and sulphuret of anti- 



ANTIMONY. 178 APLOME. 

mony, in ardinary handik The antimonial bniiied, it melts and buntM^^^Jfuude Ckitm 

medicines are powerful deobstnients, pro- Oct* 182& 

moting particularly the cuticular discharge. A NTS. See Acm (Formic). 

The union of this metallic oxide with suU APATITE. Phosphate of lime. This 

phuretted hydrogen, ought undoubtedly to f»- mineral occurs both maasiTe and crystallized. 

TOur its medicinal agency in chronic diseases The crjrstals are siz-aided prisms^ low, and 

of the skin. The kermes deserves more credit sometimes passing into the six-sided tables 

than it has hitherto received from British Lateral edges frequently truncated, and the 

physicians. fiices smooth. Lustre splendenL TVanshi- 

The compounds formed by the antimoni? cent, rarely tnmsparent Scratched by fluor 

ons and antimonic acids with the bases, have spar. Brittle. Colours, white, wine-yellow, 

not been applied to any use. Muriate of green, and red. Sp. gr. 3.1. Pbospho- 

baryta may be employed as a test for tartar resces on coals. Electric by heat and friction, 

emetic It will show, by a precipiute inso- Consists of 53.75 lime -|" 46.25 phosphoric 

luble in nitric acid, if sulphate of potash be add, by Klaproth's analysis of the variety 

present. If the crystak be regularly formed, called asparagus stone. It occurs in primi- 

mere tartar need not be susp<^ted. tive rocks ; in the tin veins of the granite of 

For its ores, saline compounds, and the St Michael's Mount, Cornwall ; near Chud- 

reduction of the metals, see Ores and Salt, leigfa in Devonshire ; at Nantes in France ; 

A fulminating antimonic powder has been in St Gothard, and in Spain ; and with mo- 
prepared by M. Serullas in the following man- lybdena in granite^ near Colbeck, Cumber- 
ner. Grind carefully together 100 parts of land. Phosphoriie is massive, forming great 
tartar emetic and 3 parts of lamp-black, or beds in the prorince of Estremadura. Yd- 
ordinary charcoal powder. Crucibles capa- lowjsh-white colour. Dull or glimmering 
ble of holding about 3 ounces of water, to lustre. Semi-hard. Fracture imperfect ; 
be only three-fourths filled, are to be ground curve foliated. Brittle. Sp.gr. 2.S. Phos* 
smooth on their edges, and nibbed inside phorescent with heat Its composition, by 
with powdered charcoal, so as to dust lightly Pelleder, is 59 lime, 34 phosphoric acid, I 
thdr surface, and prevent the subsequent carbonic acid, 2.5 fluoric add, 2 silica, 1 
adherence of the carbonaceous cone which oxide of iron, and 0.5 muriatic acid, 
remains after the caldnation. The above APHLOGISTIC LAMP. One which 
mixture being introduced into the crucible^ bums without flame. See CoMBUffnON. 
is to be covered with a layer of powdered APHANITE.* Tliis is the name given 
charcoal ; and the joinings of the cover must by Hauy to a rock apparently homogeneous^ 
6e luted. After exposure for 3 hours to a but really compound, in which amj&bole is 
good heat in a reverberatory furnace, the the predominant principle. It is a green- 
crudble must be removed, and left to cool stone, the distinction of whose parts u indls- 
for 6 or 7 hours. This interval of time is cemible. Aphanite is included among the 
necessary to allow the air, which always rocks, which the older mineralogists called 
penetrates a little way into the crudbles, to comSennett' or tapU eomeut trapetxut, 
bum the exterior coat of the fulminating APHRITE. Earth foam; schaumerde. 
mass ; otherwise, if it be taken out too re- 'This carbonate of lime occurs usually in a 
cently, there Is always an explosion. We friable state ; but sometimes solid. (>>lour, 
must then hastily enclose it, without break- almost silver-white. Massive, or in fine par- 
ing, into a glass with a wide opening. Afler tides. Sliining lustre, between semi-metal- 
some timC) it spontaneously breaks down into lie and pearly. Fracture^ curve foliated, 
fragments of different sizes, retaining all its Opaque ; soils a little. Very sofk^ and 
properties for years. When the caldnation easily cut. Feels fine and light. It ^ is 
has been conducted as above, the product is usually found in calcareous vdns, at Gera 
excessively fulminating, so that, without the in Minua, and Eisleben in Thuringia. It 
least compression, it gives rise to a violent consists, by Buchols, of 51.5 lime, 39 add» 
detonation on contact with water. 100 parts 1 water, 5.7 silica, 3.3 oxide of iron, 
of antimony, 75 of cari>uretted cream of tar- APH RIZITE. A variety of bbck toor- 
Ur, and 12 of Uunp-black, triturated together, maline. 

form also an excellent mixture. A piece of APLOME. This is commonly considered 

the size of a pea of this fulminating com- to be a variety of the garnet ; but the differ 

pound, introduced into a mass of gunpowder, rence between these minerals is this :— The 

explodes it when thrown into water. It is planes of the aplome dodecahedrons are stri- 

to the presence of potassium that the above ated parallel with thdr smaller diagonal, 

explosive property is due. 60 parts of car- which, according to Haiiy, indicates the pri* 

buretted cream of tartar, 120 of bismuth, and xnitive form to be a cube, and not a dodeca- 

1 of nitre, treated as above, yield an alloy hedron. Its colour is deep orange-brown, 

very rich in potassium, of which the smallest It is opaque, and harder than quartz. Sp* 

portion cut with scissars sparkles. When 

♦ Non manillMtus. 



ARABIC (GUM). 



^73 



ARCHIL. 



gr. it miidi less than gumet, viz. 3.44^ It 
consislsy by Laiigier*& analysts, of 40 silica, 
80 alumina, 14b 5 lime, 14 oxide of iron, 2 
oxide of manganese, 2 silica and iron. It 
is fusible into a black glass, while garnet 
fuses into a black enamel. It is found on 
the river Lena in Siberia, and also in New 
Holland. 

APOPHYLLITE. Ichthyophthalmite. 
Fish-eye stone. It is found both massive 
and crystallised. It occurs in square prisms, 
whose solid angles are sometimes replaced by 
triangular planes, or the prisms are termi- 
nated by pyramids consisting of 4 rhoroboi- 
dal planes. Structure lamellar; cross frac- 
tnre, fine-grained, uneven. External lustre, 
splendent and peculiar; internal, glistening 
and pearly. Semitransparent, or translucent. 
Moderately hard, and easUy broken. Sp. gr. 
2.49. It exfoliates, then froths, and melte 
into an opaque bead before the blowpipe. It 
consists of 51 silica, 28 lime, 4 potash, 17 
water. — Vauqurttn. It is found in the iron 
mine of Utoe in Sweden, at the copper mine 
of Fahlun, at Arendahl, Faroe, the Tyrol ; 
and Dr MacCuUoch met with a solitary cry»« 
tal in Dunvegan, in the Isle of Skye. 

APPARATUS. See Laboratory. 

APPLES. Hie juice of apples seems to 
be composed of much water, a small quantity 
of sugar analogous to that of the grape, a 
Tery small quantity of fermentescible matter, 
a Ifuge quantity of mucilage, with malic and 
acetic acids. There is no tartar in apples. 
See Cyder, and Acid (Malic). 

APYROUS. Bodies which sustain the 
action of a strong beat for a considerable time, 
without change of figure or other properties, 
have been called apyrous ; but the word is 
seldom used in the art of chemistry. It is 
svnonymous with refractory* 
' AQUAFORTIS. This name is given 
to a weak and impure nitric acid, commonly 
used in the arts. It is distinguished by the 
terms davJbU and wngUt the single being only 
half the strength of the other. The artists 
who use these acids call the more concen- 
trated acid, which is much stronger even 
than the double aquafortis, spirit vf nUrt.* 
See Acid (Nitric). 

AQUA MARINE. See Beryl. 

AQUA REGI A or REGIS. This acid, 
being compounded of a mixture of the nitric 
and muriatic adds, is now termed by chemists 
mtro>muriatic acid. 

AQUA VIT^ Ardent spirit of the first 
distillation has been distinguished in commerce 
by this name. Hie distillers of malt and me- 
Unses spirits call it low wines. 

AQUILA ALBA. One of the names 
given to the combination of muriatic acid 'and 
mercury, in that state which is commonly 
known by the denomination d mercurius 
dvids, calomel, or mild muriate of mercury* 

ARABIC (GUM). This i^ reckoned the 



purest of gums, and does not greatly difler 
from gum-senegal, vulgarly called gum-se- 
neca, which is supposed to be the strongest, 
and is on this account, as well as its greater 
plenty and cheapness, mostly used by calico 
printers and other manufacturers. The gums 
of the plum and the cherry-tree have nearly 
the same qualities as gum-arabic. All these 
substances facilitate the mixture of oils with 
water. By my analysis, gum-arabic is com- 
posed in 100 parts of 35.13 carbon, 6.08 
hydrogen, 55.79 oxygen, and possibly 3 of 
azote. 

ARABLE LANDS. It is a problem in 
chemistry, and by no means one of the least 
importance to society, to determine what are 
the requisites which distinguish fruitful landa 
from such as are less productive. See Soils, 
and Analysis of Soils. 

ARBOR DIANJE. See Silver. 

ARCHIL, ARCHILLA, ROCELLA, 
ORSEILLE. A whitish lichen, growing 
upon rocks in the Canary and Cape Verd 
Islands, which yields a rich purple tincture, 
fugitive indeed, but extremely beautiful, 
lliis weed is imported to us as it u gathered, 
lliose who prepare it for the use of the dyer, 
grind it betwixt stones, so as thoroughly to 
bruise, but not to reduce it into powder, and 
then moisten it occasionally with a strong 
spirit of urine, or urine itself mixed with 
quicklime : in a few days it acquires a pur- 
plish-red, and at length a blue colour ; in the 
first state it is called archil, in the latter lac* 
mus or litmus. 

The dyers rarely employ this dHSg by it- 
self, on account of its dearness, and the 
perishableness of its beauty. Tlie chief use 
they make of it is for giving a bloom to other 
colours, as pinks, &c. 'Diis is effected by 
passing the dyed cloth or silk through hot 
water slightly impregnated with the archil, 
llie bloom thus communicated soon decays 
upon exposure to the air. M. Hellot in- 
forms us, that by the addition of a little so- 
lution of tin, this drug gives a durable dye ; 
that its colour is at the same time changed 
toward a scarlet ; and that it is the more per- 
manent, in proportion as it recedes the more 
from its natural colour. 

Prepared archil very readily gives out its 
colour to water, to volatile spirits, and to al- 
cohol ; it is the substance prindpally made 
use of for colouring the spirits of thermome- 
ters. As exposure to the air destroys its co- 
lour upon cloth, the exclusion of the air pro- 
duces a like eifect in those hermetically s^ed 
tubes, the spirits of large thermometers be- 
coming in a few years colourless. Tlie Abb^ 
NoUet .observes, (in the French Memoirs for 
the year 1742), that the colourless spirit, upon 
breaking the tube, soon resumes its colour, 
and this for a number of times successively ; 
that a watery tincture of archil, included in 
the tubes of thermometers, lost its colour in 



AROMATICS. 



174 



ARS£N1C 



three days ; and that in an open deep Teesel 
it became colourless at the bottom, while the 
upper part retained its colour. 

A solution of archil in water, applied on 
oold marble, stains it of a beautiful violet or 
purplish-blue colour, far more durable than 
the colour which it communicates to other 
bodies. M. du Fay says he has seen pieces 
of marble stained with it, which in two yean 
had suffered no sensible change. It amks 
deep into the marble, sometimes above an 
inch, and at the same time spreads upon the 
surface, unless the edges be bounded by wax 
or some similar substance. It seems to make 
t)ie marble somewhat more brittle. 

There is a considerable consumption of an 
article of this kind manufactured in Glasgow 
by Mr Macintosh. It is much esteemed, 
and sold by the name of cudbear. We have 
seen beautiful specimens of silk thus dyed, 
the colours of which were said to be very per- 
manent, of various shades, from pink and 
crimson to a bright mazarine blue. 

Litmus is likewise used in chemistry as a 
test, either staining paper with it, or by in- 
fusing it in water, when it is very commonly, 
but with great impropriety, called tincivre of 
tumtoU. The persons by whom this article 
was prepared formerly, gave it the name of 
turnsole, pretending that it was extracted from 
the turnsole, heliotroptum tricoccum, in order 
to keep its true source a secret The tincture 
sliould not be too strong, otherwise it will have 
a riolet tinge^ which, however, may be re- 
moved by dilution. Hie light of the sun 
turns it red even in dose vessels. It may be 
made with spirit instead of water. This tinc- 
ture, or paper stained with it, is presently 
turned red by acids : and if it be first red- 
dened by a small quantity of vinegar, or some 
weak acid, its blue colour will be restored by 
an alkalL 

ARCTIZITE. See Webnerite. 

ARDENT SPIRIT. See Alcohol. 

ARENDATE. See Fistacite. 

AREOMETER. See Hydrometer. 

ARFWEDSONITE. A ferruginous va. 
riety of hornblende. Colour black ; cleav- 
age, planes much more brilliant than those of 
hornblende, which scratches it. Sp. gravity 
3. 44. It sometimes accompanies the sodalite 
fiiom Greenland. 

ARGAL. Crude tartar, in the state in 
which it is taken from the inside of wine ves- 
sels, is known in the shops by this name. 

ARGENTATE OF AMMONIA. Ful- 
minating silver. 

ARGENTINE FLOWERS OF AN- 
TIMONY. The deutoxide of the English 
chemists, or tiie antimonious acid. 

ARGILLACEOUS EARTH. See Alu- 
mina. 

A RGILLI TE. See Clay-Slate. 

AROMATICS. Plants which possess a 
fhigrant smell united with pungency, and at 



the same time are warm to the tsate, are 
called aromatics. Their peculiar flavour ap- 
pears to reside in their essential oil, and rises 
in distillation either with water or qpirit.-* 
See Oils (Essential). 

ARRACK. A spirituous liquor imported 
fWiro the East Indies. It is chiefly manufac- 
tured at Batavia, and at Goa upon the Ma- 
labar Coast. 

ARRAGONITE. This mineral occurs 
massive, in fibres of a silky lustre, and in the 
form of fibrous branches, diveiging from a 
centre, Fiopferri, It is fVequentiy crystal- 
lised in what appear at first sight to be regu- 
lar six-sided prisms. On close inspection a 
longitudinal crack will be observed down eacb 
lateral face. It occurs also in elongated oo- 
tohedrons. Lustre glassy, fracture foliated 
and fibrous. Colours greenish and peari- 
grey ; often violet and green in the middle ; 
and arranged in the direction of the fibres, so 
that the longitudinal fibres are green, the 
transverse violet-blue. Double cleavage-^ 
translucent; refracts doubly; scratches cal- 
careous spar, and sometimes even glass ; brit* 
tie; sp. grav. 2.90. It consists of carbonate 
of lime, with occasionally a littie carbonate 
of strontia. It is found in Anagon in 
Spain ; at Leogany in Salzburg; at Marien- 
berg in Saxony ; Sceraing in the T^rol ; and 
in the carities of basalt near Glasgow. The 
finest specimens of the Flos-ferri ramifications 
come from the mines of Eiaenen in Stiria: 
beautiful specimens have been also fbund in 
tfie Dufton lead mines in England, in the 
workings of an old coal mine, called Lufton- 
bill pit, near Durham. It also occurs in the 
trap rocks of Scotiand. 

ARROWROOT. This fecula is obtained 
from the roots of the Maranta Anindinacea, 
a plant cultivated in the West Indies. The 
roots are washed, and beat to a pulp in large 
wooden mortars, which is afterwards sepa- 
rated from fibrous matter by agitation with 
water in large tubs. The milky liquor is 
passed through a sieve, and allowed to sub- 
side. When thoroughly washed and dried, 
it constitutes this nutritive species of starch, 
very analogous to well purified potato starch. 

ARSENIC, in die metallic state, is of a 
bluish-white colour, subject to tarnish, and 
grows first yellowish, then black, by exposure 
to air. It is brittie, and when broken ex- 
hibits a laminated texture. Its specific gra- 
vity is 5.76dL In close vessels it sublimes 
entire at 356^ F., but bums with a small 
fiaroe if oxygen be present' 

The arsenic met with in commerce has 
the form of a white oxide^ It is brought 
chiefly from the cobalt works in Saxony, 
where taffre is made. Cobalt ores contain 
much arsenic, which is driven off by long 
torrefaction. The ore is thrown into a fur- 
nace, resembling a baker's oven, with a flue, 
or horisontal chimney, neariy two hundred 



ARSENIC 



176 



ARSENIC. 



yards km|^ into which the fumes pass, and 
are condensed into a greyish or blackish pow- 
der. TUs b refined by a second sublimation 
in close vessels, with a little potash to detain 
the impurities. As the beat is conaderable, 
it melts the sublimed flowers into those crys- 
talline masses which are met with in com- 
merce. See Acid (ARaENious). 

• The metal may be obtained from this, 
either by quickly fusing it together with twice 
its wdght of soft soap and an equal quantity 
of alkaliy and pouring it out, when fused, in- 
to a hot iron cone ; or by mixing it in pow- 
der with oil, and exposing it in a matrass to a 
sand heat. This process is too offensive 
to be performed except in the open air, or 
where a current of air carries off the fumes. 
The decomposed oil first rises ; and the ar- 
senic is afterwards sublimed in the form of a 
flaky metallic substance. It may likewise be 
obtained by mixing two parts of the arsenious 
add with one of black flux ; putting the 
mixture into a crucible with another inverted 
over it, and luted to it with clay and sand ; 
and 4q>plying a red heat to the lower crucible. 
The metal will be reduced, and line 'the in- 
side of the upper crucible. 

It is among the most combustible of the 
metals, bums with a blue flame and garlic 
smeU, and sublimes in the state of arsenious 
add. 

Chloride of Arsenic, One part of arsenious 
acid, with ten parts of concentrated sulphuric 
addy is to be put into a tubulated retort, and 
the temperature raised to nearly 212^ F. 
Fragments of fused conunon salt are then to 
be thrown in by the tubulure. By continuing 
the heat, with the successive addition of com- 
mon salt, protodiloride of arsenic is obtained. 
It falls, drop by drop, from the beak of the re- 
tort, and may be collected in cooled vessels. 
'—Dumati Ann* de Chimie, xxxiii. 360. 

Concentrated sulphuric add does not at- 
tack arsenic when cold ; but if it be boiled 
upon this metal, sulphurous add gas is emit- 
ted, a small quantity of sulphur sublimes, 
and the arsenic is reduced to an oxide. 

Nitric add readily attacks arsenic, and 
converts it into arsenious acid, or, if much be 
employed, into arsenic add. 

Boiling muriatic add dissolves arsenic, but 
afiects it very little when cold. This solution 
aSbrds predpitates upon the addition of al- 
kalis. The addition of a little nitric add ex- 
pedites the solution ; and thb solution, first 
heated and condensed in a close vessel, is 
wholly sublimed into a thick liquid, formerly 
termed butter of artenic. Thrown in powder 
into chlorine gas, it burns with a bright white 
flame^ and is converted into a chloride. 

None of the earths or alkalis act upon it, 
unless it be boiled a long while in fine pow- 
der, in a large proportion of alkaline solu- 
tion. 

Nitrates detonate with arsenic, convert it 



into arsenic acid, and this, combining with 
the base of the nitrate, forms an arseniate, 
that remains at the bottom of the vessel. 

Muriates have no action upon it ; but if 
three parts of chlorate of potash be mixed 
with one part of arsenic in fine powder, 
which must be done with great precaution 
and a very light hand, a very small quantity 
of this mixture, placed on an anvil, and 
struck with a hammer, will explode with 
flame and a considerable report; if touched 
with fire, it will burn with considerable rapi- 
dity ; and if thrown .into concentrated sul- 
phuric acid, at the instant of contact a flame 
rises into the air like a flash of lightnings 
which is so bright as to dazzle the eye. 

Arsenic readily combines with sulphur by 
fusion and sublimation, and forms a yellow 
compound caUed orpimerUt or a red called 
realgar. The nature of these, and thdr dif- 
ference, are not accurately known ; but Four- 
croy considers the first as a combination of 
sulphur with the oxide, and the second as a 
combination of sulphur with the metal itsellv 
as he found the red sulphuret converted into 
the yellow by the action of acids. 

In order to test the opinion entertained by 
certain physidans, that sulphuret of arsenic is 
innocuous, M. Orfila made several experi- 
ments with it, which shewed clearly its dele- 
terious nature. On applying 50 or 60 grains 
of the yellow sulphuret of arsenic to the 
thighs of dogs, these animals suffered in the 
same manner as by other arsenical prepara- 
tions, and died in from 48 to 60 hours. The 
native orpiment of Tojova poisoned and 
caused death in two days. Death was pro- 
duced in six days by 40 grains of native 
realgar from Harpnike in Transylvania. 
Hence it is shewn, that the sulphurets of ar- 
senic, dther natural or artificial, and when 
^free from white arsenic, are still poisonous. 
M. Orfila proved by similar experiments, 
that the sulphurets of lead, copper, and mer- 
cury, (red as well as black), were innocuous. 
Most metals unite with arsenic, which exists 
in the metallic state in such alloys as possess 
the metallic brilliancy. 

Iodine and arsenic unite, forming an 
iodide of a dark purple-red colour, possess- 
ing the properties of an add. It is soluble 
in water, and its solution forms a soluble 
compound with potash. Arsenic combines 
with hydrogen into a very noxious cono- 
pound, called arsenuretted hydrogen gas. 
To prepare it, fuse in a covered crudble three 
parts of granulated tin, and one of metallic 
arsenic in powder; and submit this alloy, 
broken in pieces, to the action of muriatic 
add in a glass retort. On applying a mo 
derate heat, the arsenuretted hydrogen comes 
over, and may be received in a mercurial or 
water pneumatic trough. Fh>tomuriate of 
tin remains in the retort When one of 
anemc is used for 15 of tin, thp former metal 



ARSENIC. 



176 



ASBESTOa 



u entirely carried off in the evolTed hydrogen. 
100 parts of this gas contain 140 of hydro- 
gen, as is proved by heating it with tin. 
Its specific gravity, according to Sir H. 
Davy, is 0.5552 ; aooonding to Trommsdorf, 
0.529a Stromeyer states, that by a cold of 
— 22^ it condenses into a liquid. Exploded 
with twice its bulk of oxygen, water and 
oxide of arsenic are formed. When arsenu- 
retted hydrogen issuing from a tube is set on 
fire^ it deposits a hydruret of arsenic. Sul- 
phur, potassium, sodium, and tin, decompose 
this gas, combine with its metal, and in the 
case of sulphur, sulphuretted hydrogen re- 
sults. By subtracting from the specific gra- 
vity of the arsenuretted gas that of hydrogen 
gas X T^» ^c ^^^ ^ proportion of arse- 
nic present; 0.55520— 0.09716 ss 0.45804 
s= the arsenic in 100 measures of arsenuret- 
ted hydrogen ; which gives the proportion by 
weight of about 5 arsenic to 1 hydrogen ; but 
Stromeyer*s analysis by nitric add gives about 
50 arsenic to 1 hydrogen, which is probably 
much nearer the true composition. A prime 
equivalent of hydrogen is to one of arsenic as 
1 to 76 ; and two consequently as 1 to 38. 
Gdilen fell a victim to his researches on this 
gas; and therefore the new experiments re- 
quisite to elucidate its constitution must be 
.conducted with circumspection. If chlorine 
be added to a mixture of arsenuretted and 
sulphuretted hydrogen, the bulk diminishes, 
and yellow-coloured flakes are deposited. 
Concentrated nitric acid occasions an explo- 
sion in this gas, preceded by nitrous fumes ; 
but if the add be diluted, a silent decompo- 
sition of the gas is effected. The density of 
the hydrogen in this compound gas is 
9.09716. Tlierefore, by Stromeyer's analysis, 
we have this proportion to calculate the spe^ 
dfic gravity of the gas; 2.19 : a09716 : : 
(2.19 + 106) : 4.827; a quantity nearly^ 
9 times greater than what experiment has' 
given. 

This gas extinguishes flame, and instantly 
destroys animal life. Water has no effect 
upon it. From the experiments of Sir H. 
Davy and MM. Gay Lussac and Tlienard, 
there appears to be a solid compound of hy- 
drogen and arsenic, or a hydruret. It is 
formed by acting with the negative pole of a 
voltaic battery on arsenic plunged in water. 
It is reddish-brown, without lustre, taste, or 
smdl. It is not decomposed at a heat ap- 
proaching to cherry-red ; but at this temper 
rature it absorbs oxygen, while water and 
arsenious add are formed, with the evolution 
of heat and light. The proportion of the two 
constituents is not known. 

Arsenic is used in a variety of arts. It 
enters into metallic combinations wherein a 
white colour is required. Glass manufac- 
turers use it ; but its effect in the composi- 
tion of glass does not seem to be deariy ex- 
plained. Orpiment and realgar are used as 



pigments. See Aans (Absbnic^ and Aase- 
Nious), and Salt. 

ASAFGBTIDA is obtained from a large 
umbelliferous plant growing in Persia. The 
root resembles a large parsnep, externally of 
a black colour: on cutting it transversely, the 
asafoetida exudes in form of a white thick 
juice, like cream ; which, from exposure to 
the air, becomes yellower and yellower, and 
at last of a dark brown colour. It is very 
apt to run into putrefaction ; and hence those 
who collect it carefully defend it from the 
sun. Tlie fresh juice has an excessively strong 
smell, which grows weaker and weaker upon 
keeping : a «ingle dram of the fresh fluid 
juice smells more than a hundred pounds of 
the dry asafoetida brought to us. The Per- 
sians are conunonly obliged to hire ships on 
purpose for its carriage, as scarcely any one 
will receive it along with other commodities, 
its stench infecting every thing that comes 
near it. 

Tlie common asafoetida of the shops is of a 
yellowish or brownish colour, unctuous and 
tough, of an acrid or biting taste, and a 
strong 'disagreeable smell, resembling that of 
garlic. From four ounces Neumann obtain- 
ed, by rectified spirit^ two ounces six drams 
and a half of resinous extract ; and after- 
ward, by water, three drams and half a 
scruple of gummy extract ; about six drams 
and a scruple of earthy matter remaining 
undissolved. On implying water at first, be 
gained, from four ounces, one ounce three 
scruples and a half of gummy extract. 

Asafoetida is administered in